Patent Application
20230159961
Plant diterpenes occupy a unique molecular space with critical pharmaceutical applications over a diverse spectrum including anti-cancer, anti-microbial and immunomodulatory properties. In addition, plant-derived terpenoids have a wide range of commercial and industrial uses. Examples of uses for terpenoids include specialty fuels, agrochemicals, fragrances, nutraceuticals and pharmaceuticals. However, currently available methods for synthesis, extraction, and purification of terpenoids from the native plant sources have limited economic sustainability. Moreover, currently available methods for do not provide the substrates and methods for biosynthesis of non-natural terpenoids.
The enzymes of terpene synthesis pathways are evolutionarily optimized to deliver bioactive molecules, novel molecular scaffolds and chemistry. Yet, cost-effective synthesis and access to analogs of plant diterpenoids and their derivatives is technologically limited on the levels of isolation, purification, detection and synthesis.
While the terpene biosynthetic enzymes catalyze some of nature's most complex chemistries, the natural entry into terpenoid pathways is limited to a single precursor, geranylgeranyl diphosphate (GGPP). And although GGPP is a compound having all-trans double bonds, it has been recently shown that the cis-prenyl is also relevant in other plant species. See, e.g., https://doi.org/10.1111/tpj.14957. However, as described herein a variety of non-natural substrates can be used by terpene biosynthetic enzymes to produce structurally diverse unnatural diterpene analogs and unnatural terpene key intermediates for further functionalization. Products formed using the non-natural substrates and methods described herein are bioactive and compared to related natural compounds they have modulated specificity against their molecular targets.
For example, methods are described herein that include contacting an unnatural substrate with one or more enzymes that can synthesize a terpene to generate a primary terpene product.
New substrates for terpene biosynthesis and methods for making new types of terpenes are described herein. Diterpenes occupy a unique molecular space with critical pharmaceutical applications over a diverse spectrum including anti-microbial, anti-cancer, immunomodulatory and psychoactive properties. Many diterpenoids are currently recognized as “drugs” (351 of over 12,500 are listed in the Dictionary of Natural Products, Taylor and Francis Group, DNP 28.1). A key challenge, however, is optimization of these compounds, and derivatization is usually not synthetically tractable.
While terpene synthase enzymes catalyze some of nature's most complex chemistries, the natural entry into the pathways is limited to a single precursor, geranylgeranyl diphosphate (GGPP), a precursor to almost all of natural diterpenes. Small molecule libraries for novel and promising leads for further manipulation are in demand as in vitro tools to investigate disease mechanisms, as in vivo probes, and to serve as starting points for the development of effective drugs. New compound libraries with high sp3-character, rather than the sp2-character typically observed in existing libraries, are generally missed by current technologies for library production (Karaki et al. Chem Med Chem (2019)). A unique three-dimensional space, or molecular complexity is correlated with success in the transition from discovery, to clinical testing, to approved drugs (Lovering, Medchemcomm 4: 515-519 (2013); Lovering et al. J. Med. Chem. 52, 6752-6756 (2009)). Complexity is measured by two descriptors, the fraction of tetrahedral sp3 carbons (Fsp3) where Fsp3 equals the number of sp3 hybridized carbons by total carbon count, and the chiral carbon count.
As described herein the terpene synthesis pathway is unexpectedly modular and the enzymes involved in terpene synthesis are surprisingly promiscuous. Unique, novel substrates for terpenes are described herein that are useful for making diverse types of new terpenoids.
Terpenes are the oldest and structurally most complex family of specialized metabolites on the planet. The class of diterpenes with their characteristic C20 scaffold is structurally diverse with over 12,500 compounds reported with a significant spectrum of pharmaceutical applications (Banerjee & Hamberger, P450s controlling metabolic bifurcations in plant terpene specialized metabolism. Phytochem. Rev. (2017)). Their molecular weight, extraordinary high fraction of spa centers (Fsp3 often >0.8), number of stereogenic centers, and regiospecific and stereospecific heteroatom functionalization (exceeding 95% with 2+ oxygens) makes them superior candidates for the discovery and development of novel therapeutics. The structural complexity of a representative diterpenoid is illustrated by the diterpene scaffold of stevioside shown below, which has an Fsp3 of 0.9.
The enzymes of terpene synthesis pathways are evolutionarily optimized to deliver bioactive molecules, novel molecular scaffolds, and novel chemistries, with pharmaceutical targets and modes of action identified only for a few, due to their limited availability (e.g., Picato®, Taxol®, forskolin, and salvinorin).
Cost-effective synthesis and access to analogs of plant diterpenoids and their derivatives is technologically limited by the levels of isolation, purification, detection and synthesis. Isolation and purification for screening of their pharmaceutical properties and clinical development are severely impeded by a lack of sustainable supply through their natural sources where diterpenoids accumulate in complex mixtures of closely related, but unwanted compounds. Formal chemical synthesis is economically challenging, as targets are still deconstructed one at a time, and even the most elegant biomimetic routes can be mind-bending in their complexity (Jorgensen et al. Science 341: 878-882 (2013); Appendino et al. Angew. Chemie Int. Ed. 53, 927-929 (2014)).
Synthetic Biology can alleviate the bottleneck of access. However, despite earlier successes by others (C15 anti-malaria drug artemisinin, Paddon et al. Nature 496: 528— 32 (2013)) and by the inventors (C20 drugs forskolin and phorbol-ester lead molecule jolkinol C, Luo et al. Proc. Natl. Acad. Sci. 113(34): E5082-9 (2016); Pateraki et al. Elife 6, (2017)), these approaches were limited to single targets and are incompatible with the need to generate diversified libraries that can be structurally manipulated by terpene synthases and other enzymes.
Jolkinol C represents the scaffold of the class of lathyrane-type phorbol esters with a macrocyclic, irregular structure. Compounds of this class exhibit potent antineoplastic activities against multidrug-resistant carcinoma lines. The NF-KB transcription factor provides a model system to study the posttranslational activation of a phorbol-ester-inducible transcription factor. The induction of NF-KB proceeds directly from protein kinase C upon binding of phorbol esters. The labdane-type diterpene forskolin is an important tool to raise cellular levels of cyclic AMP, a second messenger necessary for responses to hormones and cell communication. The mechanism proceeds via direct activation of all membrane bound isoforms of the adenylate cyclase. Acyl-analogs of forskolin were shown to strongly modulate the potency. The inventors have found that individual enzymes of both pathways, when probed with a small number of substrates, showed multifunctionality and promising promiscuity. In view of the utility of compounds similar to jolkinol C and forskolin the inventors have defined jolkinol C and forskolin functionalization pathways and identified diterpene scaffolds derived from GGPP, for biosynthesis using unnatural substrate scaffolds.
Described herein is a chemical strategy to bioprocess libraries of plant-inspired small molecules of the diterpene class. Novel synthetic substrate analogs are provided (i) to interrogate the intricate mechanism and substrate tolerance of terpene cyclization leading to unnatural decalin-core and irregular terpenes, (ii) to generate a panel of unnatural terpene key intermediates for functionalization through two pharmaceutically relevant pathways, and (iii) to characterize the function of such compounds with bioassays.
Despite their structural complexity, the biosynthesis routes of diterpenes are modular. This is illustrated in
Enzymatic bioprocessing of novel pharmaceutical candidates is increasingly important for securing access to relevant chemistries, scalability of production, and long-term reduction in cost for synthesis of scaffolds. Genetic information was used to reconstruct the pathways to the pharmacologically active cyclic AMP booster forskolin, and jolkinol C (shown in
A degree of substrate promiscuity was unexpectedly observed on all three hierarchical levels of the biosynthetic route, indicating that the enzymes involved in such biosynthesis have an ability to act on substrates that they do not normally encounter and that the enzymes can convert a broader range of intermediates to diverse end products.
Taking advantage of natural substrate promiscuity, precursor-directed biosynthesis was used to generate variants of the drugs in the family of non-ribosomal peptides, polyketides and non-natural indole alkaloids. Modification of natural products can provide analogs with improved or novel medicinal properties. To that end, the disclosure relates to substrates of the formula (I) or (II):
wherein: m is an integer from 0 to 3 (e.g., 1 or 2), with the understanding that if m is 2 or 3, each repeating subunit can be the same or different;
n is an integer from 0 to 1;
the dashed lines represent a double bond when R3′ and R4′ are absent or when R5′ and R6′ are absent ,
A and A′ are each independently cycloalkyl, aryl or heterocyclyl, each of which can be optionally substituted;
X1 is a heteroatom, —X3-alkyl, -alkyl-X3— or alkyl, wherein X3 is a heteroatom or alkyl or X1 is:
R1 and R2 form a double bond or an epoxide;
each R′, R1′, R2, R2′, and R3—R6 is, independently, H, alkyl, halo, aryl, and alkylaryl;
R3′ and R4′ are absent or R3′ and R4′, together with the carbon atoms to which they are attached, form an epoxide, a cycloalkyl group, an aryl group or a heterocyclyl group;
R5′ and R6′ are absent or R5′ and R6′, together with the carbon atoms to which they are attached, form an epoxide, a cycloalkyl group, an aryl group or a heterocyclyl group;
X2 is a bond, alkenyl or acyl; and
X4 is a absent, a heteroatom or alkyl;
with the proviso that the compound of the formula (I) is not a compound of the formula:
Examples of compounds of the formula (I) include compounds of the formula:
Examples of the formula (II) include compounds of the formula:
Examples of compounds of the formula (I) include compounds wherein if X1 is a heteroatom, the heteroatom is oxygen. Other examples of compounds of the formula (I) include compounds wherein X3 is oxygen or C1-C5-alkyl, such as —CH2— and C2-C3-alkyl. Still other examples of compounds of the formula (I) include compounds wherein R3-R6 are each H or C1-C5-alkyl, such as methyl and C2-C3-alkyl. Still other examples of compounds of the formula (I) include compounds wherein R3 and R5 are each H or C1-C5-alkyl, such as methyl and C2-C3-alkyl; and R4 and R6 are each H. Yet other examples of compounds of the formula (I) include compounds wherein m is 1 or 2. In other examples, m is 0. Other examples of compound of the formula (I) include compounds wherein X2 is an alkenyl group of the formula:
or an acyl group of the formula:
Examples of compounds of the formula (I) include compounds of the formulae:
The compounds of the formula (I) or (II) can be enzymatically transformed into terpenoids having compound cores of the formula:
which correspond to the cores of stevioside, Taxol®, Forskolin, Picato®, and Salvinorin, Casbene, CPP respectively; or the core shared by CPP, LPP, PgPP, and KPP, namely:
and derivatives thereof, wherein derivatives can comprise additional double bonds, alkyl groups, hydroxy groups, acyl groups, and the like, dispersed about the cores.
As used herein, the term “heteroatom” refers to heteroatom such as, but not limited to, NR7, O, and SO, wherein R7 is H, alkyl or arylalkyl, and x is 0, 1 or 2.
The term “alkyl” as used herein refers to substituted or unsubstituted straight chain, branched and cyclic, saturated mono- or bi-valent groups having from 1 to 20 carbon atoms, 10 to 20 carbon atoms, 12 to 18 carbon atoms, 6 to about 10 carbon atoms, 1 to 10 carbons atoms, 1 to 8 carbon atoms, 2 to 8 carbon atoms, 3 to 8 carbon atoms, 4 to 8 carbon atoms, 5 to 8 carbon atoms, 1 to 6 carbon atoms, 2 to 6 carbon atoms, 3 to 6 carbon atoms, or 1 to 3 carbon atoms. Examples of straight chain mono-valent (C1-C20-alkyl groups include those with from 1 to 8 carbon atoms such as methyl (i.e., CH3), ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl groups. Examples of branched mono-valent (C1-C20-alkyl groups include isopropyl, iso-butyl, sec-butyl, t-butyl, neopentyl, and isopentyl. Examples of straight chain bi-valent (C1-C20)alkyl groups include those with from 1 to 6 carbon atoms such as —CH2—, —CH2CH2—, —CH2CH2CH2—, —CH2CH2CH2CH2—, and —CH2CH2CH2CH2CH2—. Examples of branched bi-valent alkyl groups include —CH(CH3)CH2— and —CH2CH(CH3)CH2—. Examples of cyclic alkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.1]hexyl, and bicyclo[2.2.1]heptyl. Cycloalkyl groups further include polycyclic cycloalkyl groups such as, but not limited to, norbornyl, adamantyl, bornyl, camphenyl, isocamphenyl, and carenyl groups, and fused rings such as, but not limited to, decalinyl, and the like. In some embodiments, alkyl includes a combination of substituted and unsubstituted alkyl. As an example, alkyl, and also (C1)alkyl, includes methyl and substituted methyl. As a particular example, (C1)alkyl includes benzyl. As a further example, alkyl can include methyl and substituted (C2-C8)alkyl. Alkyl can also include substituted methyl and unsubstituted (C2-C8)alkyl. In some embodiments, alkyl can be methyl and C2-C8 linear alkyl. In some embodiments, alkyl can be methyl and C2-C8 branched alkyl. The term methyl is understood to be —CH3, which is not substituted. The term methylene is understood to be —CH2-, which is not substituted. For comparison, the term (C1)alkyl is understood to be a substituted or an unsubstituted —CH3 or a substituted or an unsubstituted —CH2—. Representative substituted alkyl groups can be substituted one or more times with any of the groups listed herein, for example, cycloalkyl, heterocyclyl, aryl, amino, haloalkyl, hydroxy, cyano, carboxy, nitro, thio, alkoxy, and halogen groups. As further example, representative substituted alkyl groups can be substituted one or more fluoro, chloro, bromo, iodo, amino, amido, alkyl, alkoxy, alkylamido, alkenyl, alkynyl, alkoxycarbonyl, acyl, formyl, arylcarbonyl, aryloxycarbonyl, aryloxy, carboxy, haloalkyl, hydroxy, cyano, nitroso, nitro, azido, trifluoromethyl, trifluoromethoxy, thio, alkylthio, arylthiol, alkylsulfonyl, alkylsulfinyl, dialkylaminosulfonyl, sulfonic acid, carboxylic acid, dialkylamino and dialkylamido. In some embodiments, representative substituted alkyl groups can be substituted from a set of groups including amino, hydroxy, cyano, carboxy, nitro, thio and alkoxy, but not including halogen groups.
The terms “halo,” “halogen,” or “halide” group, as used herein, by themselves or as part of another substituent, mean, unless otherwise stated, a fluorine, chlorine, bromine, or iodine atom.
The term “acyl” as used herein refers to a group containing a carbonyl moiety wherein the group is bonded via the carbonyl carbon atom. The carbonyl carbon atom is also bonded to another carbon atom, which can be part of a substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, cycloalkyl, heterocyclyl, group or the like.
The term “alkenyl” as used herein refers to substituted or unsubstituted straight chain, branched and cyclic, saturated mono- or bi-valent groups having at least one carbon-carbon double bond and from 2 to 20 carbon atoms, 10 to 20 carbon atoms, 12 to 18 carbon atoms, 6 to about 10 carbon atoms, 2 to 10 carbons atoms, 2 to 8 carbon atoms, 3 to 8 carbon atoms, 4 to 8 carbon atoms, 5 to 8 carbon atoms, 2 to 6 carbon atoms, 3 to 6 carbon atoms, 4 to 6 carbon atoms, 2 to 4 carbon atoms, or 2 to 3 carbon atoms. The double bonds can be trans or cis orientation. The double bonds can be terminal or internal. The alkenyl group can be attached via the portion of the alkenyl group containing the double bond, e.g., vinyl, propen-1-yl and buten-1-yl, or the alkenyl group can be attached via a portion of the alkenyl group that does not contain the double bond, e.g., penten-4-yl. Examples of mono-valent (C2-C20)-alkenyl groups include those with from 1 to 8 carbon atoms such as vinyl, propenyl, propen-1-yl, propen-2-yl, butenyl, buten-1-yl, buten-2-yl, sec-buten-1-yl, sec-buten-3-yl, pentenyl, hexenyl, heptenyl and octenyl groups. Examples of branched mono-valent (C2-C20)-alkenyl groups include isopropenyl, iso-butenyl, sec-butenyl, t-butenyl, neopentenyl, and isopentenyl. Examples of straight chain bi-valent (C2-C2o)alkenyl groups include those with from 2 to 6 carbon atoms such as —CHCH—, —CHCHCH2—, —CHCHCH2CH2—, and —CHCHCH2CH2CH2—. Examples of branched bi-valent alkyl groups include —C(CH3)CH— and —CHC(CH3)CH2—. Examples of cyclic alkenyl groups include cyclopentenyl, cyclohexenyl and cyclooctenyl. It is envisaged that alkenyl can also include masked alkenyl groups, precursors of alkenyl groups or other related groups. As such, where alkenyl groups are described it, compounds are also envisaged where a carbon-carbon double bond of an alkenyl is replaced by an epoxide or aziridine ring. Substituted alkenyl also includes alkenyl groups which are substantially tautomeric with a non-alkenyl group. For example, substituted alkenyl can be 2-aminoalkenyl, 2-alkylaminoalkenyl, 2-hydroxyalkenyl, 2-hydroxyvinyl, 2-hydroxypropenyl, but substituted alkenyl is also understood to include the group of substituted alkenyl groups other than alkenyl which are tautomeric with non-alkenyl containing groups. In some embodiments, alkenyl can be understood to include a combination of substituted and unsubstituted alkenyl. For example, alkenyl can be vinyl and substituted vinyl. For example, alkenyl can be vinyl and substituted (C3-C8)alkenyl. Alkenyl can also include substituted vinyl and unsubstituted (C3-C8)alkenyl. Representative substituted alkenyl groups can be substituted one or more times with any of the groups listed herein, for example, monoalkylamino, dialkylamino, cyano, acetyl, amido, carboxy, nitro, alkylthio, alkoxy, and halogen groups. As further example, representative substituted alkenyl groups can be substituted one or more fluoro, chloro, bromo, iodo, amino, amido, alkyl, alkoxy, alkylamido, alkenyl, alkynyl, alkoxycarbonyl, acyl, formyl, arylcarbonyl, aryloxycarbonyl, aryloxy, carboxy, haloalkyl, hydroxy, cyano, nitroso, nitro, azido, trifluoromethyl, trifluoromethoxy, thio, alkylthio, arylthiol, alkylsulfonyl, alkylsulfinyl, dialkylaminosulfonyl, sulfonic acid, carboxylic acid, dialkylamino and dialkylamido. In some embodiments, representative substituted alkenyl groups can be substituted from a set of groups including monoalkylamino, dialkylamino, cyano, acetyl, amido, carboxy, nitro, alkylthio and alkoxy, but not including halogen groups. Thus, in some embodiments, alkenyl can be substituted with a non-halogen group. In some embodiments, representative substituted alkenyl groups can be substituted with a fluoro group, substituted with a bromo group, substituted with a halogen other than bromo, or substituted with a halogen other than fluoro. For example, alkenyl can be 1-fluorovinyl, 2-fluorovinyl, 1,2-difluorovinyl, 1,2,2-trifluorovinyl, 2,2-difluorovinyl, trifluoropropen-2-yl, 3,3,3-trifluoropropenyl, 1-fluoropropenyl, 1-chlorovinyl, 2-chlorovinyl, 1,2-dichlorovinyl, 1,2,2-trichlorovinyl or 2,2-dichlorovinyl. In some embodiments, representative substituted alkenyl groups can be substituted with one, two, three or more fluoro groups or they can be substituted with one, two, three or more non-fluoro groups.
The term “alkynyl” as used herein, refers to substituted or unsubstituted straight and branched chain alkyl groups, except that at least one triple bond exists between two carbon atoms. Thus, alkynyl groups have from 2 to 50 carbon atoms, 2 to 20 carbon atoms, 10 to 20 carbon atoms, 12 to 18 carbon atoms, 6 to about 10 carbon atoms, 2 to 10 carbons atoms, 2 to 8 carbon atoms, 3 to 8 carbon atoms, 4 to 8 carbon atoms, 5 to 8 carbon atoms, 2 to 6 carbon atoms, 3 to 6 carbon atoms, 4 to 6 carbon atoms, 2 to 4 carbon atoms, or 2 to 3 carbon atoms. Examples include, but are not limited to ethynyl, propynyl, propyn-1-yl, propyn-2-yl, butynyl, butyn-1-yl, butyn-2-yl, butyn-3-yl, butyn-4-yl, pentynyl, pentyn-1-yl, hexynyl, Examples include, but are not limited to —C≡CH, —C≡C(CH3), —C≡C(CH2CH3), —CH2C≡CH, —CH2C≡C(CH3), and —CH2C≡C(CH2CH3) among others.
The term “aryl” as used herein refers to substituted or unsubstituted univalent groups that are derived by removing a hydrogen atom from an arene, which is a cyclic aromatic hydrocarbon, having from 6 to 20 carbon atoms, 10 to 20 carbon atoms, 12 to 20 carbon atoms, 6 to about 10 carbon atoms or 6 to 8 carbon atoms. Examples of (C6-C20)aryl groups include phenyl, napthalenyl, azulenyl, biphenylyl, indacenyl, fluorenyl, phenanthrenyl, triphenylenyl, pyrenyl, naphthacenyl, chrysenyl, anthracenyl groups. Examples include substituted phenyl, substituted napthalenyl, substituted azulenyl, substituted biphenylyl, substituted indacenyl, substituted fluorenyl, substituted phenanthrenyl, substituted triphenylenyl, substituted pyrenyl, substituted naphthacenyl, substituted chrysenyl, and substituted anthracenyl groups. Examples also include unsubstituted phenyl, unsubstituted napthalenyl, unsubstituted azulenyl, unsubstituted biphenylyl, unsubstituted indacenyl, unsubstituted fluorenyl, unsubstituted phenanthrenyl, unsubstituted triphenylenyl, unsubstituted pyrenyl, unsubstituted naphthacenyl, unsubstituted chrysenyl, and unsubstituted anthracenyl groups. Aryl includes phenyl groups and also non-phenyl aryl groups. From these examples, it is clear that the term (C6-C20)aryl encompasses mono- and polycyclic (C6-C20)aryl groups, including fused and non-fused polycyclic (C6-C20)aryl groups. The term “heterocyclyl” as used herein refers to substituted aromatic, unsubstituted aromatic, substituted non-aromatic, and unsubstituted non-aromatic rings containing 3 or more atoms in the ring, of which, one or more is a heteroatom such as, but not limited to, N, O, and S. Thus, a heterocyclyl can be a cycloheteroalkyl, or a heteroaryl, or if polycyclic, any combination thereof. In some embodiments, heterocyclyl groups include 3 to about 20 ring members, whereas other such groups have 3 to about 15 ring members. In some embodiments, heterocyclyl groups include heterocyclyl groups that include 3 to 8 carbon atoms (C3-C8), 3 to 6 carbon atoms (C3-C6) or 6 to 8 carbon atoms (C6-C8). A heterocyclyl group designated as a C2-heterocyclyl can be a 5-membered ring with two carbon atoms and three heteroatoms, a 6-membered ring with two carbon atoms and four heteroatoms and so forth. Likewise, a C4-heterocyclyl can be a 5-membered ring with one heteroatom, a 6-membered ring with two heteroatoms, and so forth. The number of carbon atoms plus the number of heteroatoms equals the total number of ring atoms. A heterocyclyl ring can also include one or more double bonds. A heteroaryl ring is an embodiment of a heterocyclyl group. The phrase “heterocyclyl group” includes fused ring species including those that include fused aromatic and non-aromatic groups. Representative heterocyclyl groups include, but are not limited to piperidynyl, piperazinyl, morpholinyl, furanyl, pyrrolidinyl, pyridinyl, pyrazinyl, pyrimidinyl, triazinyl, thiophenyl, tetrahydrofuranyl, pyrrolyl, oxazolyl, imidazolyl, triazyolyl, tetrazolyl, benzoxazolinyl, and benzimidazolinyl groups. For example, heterocyclyl groups include, without limitation:
wherein X5 represents H, (C1-C20)alkyl, (C6-C20)aryl or an amine protecting group (e.g., a t-butyloxycarbonyl group) and wherein the heterocyclyl group can be substituted or unsubstituted. A nitrogen-containing heterocyclyl group is a heterocyclyl group containing a nitrogen atom as an atom in the ring. In some embodiments, the heterocyclyl is other than thiophene or substituted thiophene. In some embodiments, the heterocyclyl is other than furan or substituted furan.
The term “aralkyl” and “arylalkyl” as used herein refers to alkyl groups as defined herein in which a hydrogen or carbon bond of an alkyl group is replaced with a bond to an aryl group as defined herein. Representative aralkyl groups include benzyl, biphenylmethyl and phenylethyl groups and fused (cycloalkylaryl)alkyl groups such as 4-ethyl-indanyl. Aralkenyl groups are alkenyl groups as defined herein in which a hydrogen or carbon bond of an alkyl group is replaced with a bond to an aryl group as defined herein.
The term “substituted” as used herein refers to a group that is substituted with one or more groups including, but not limited to, the following groups: halogen (e.g., F, Cl, Br, and I), R, OR, ROH (e.g., CH2OH), OC(O)N(R)2, CN, NO, NO2, ONO2, azido, CF3, OCF3, methylenedioxy, ethylenedioxy, (C3-C20)heteroaryl, N(R)2, Si(R)3, SR, SOR, SO2R, SO2N(R)2, SO3R, P(O)(OR)2, OP(O)(OR)2, C(O)R, C(O)C(O)R, C(O)CH2C(O)R, C(S)R, C(O)OR, OC(O)R, C(O)N(R)2, C(O)N(R)OH, OC(O)N(R)2, C(S)N(R)2, (CH2)0-2N(R)C(O)R, (CH2)0-2N(R)N(R)2, N(R)N(R)C(O)R, N(R)N(R)C(O)OR, N(R)N(R)CON(R)2, N(R)SO2R, N(R)SO2N(R)2, N(R)C(O)OR, N(R)C(O)R, N(R)C(S)R, N(R)C(O)N(R)2, N(R)C(S)N(R)2, N(COR)COR, N(OR)R, C(═NH)N(R)2, C(O)N(OR)R, or C(═NOR)R wherein R can be hydrogen, (C1-C20)alkyl, (C6-C20)aryl, heterocyclyl or polyalkylene oxide groups, such as polyalkylene oxide groups of the formula —(CH2CH20)f—R—OR, —(CH2CH2CH20)g—R—OR, —(CH2CH20)f(CH2CH2CH20)g—R—OR each of which can, in turn, be substituted or unsubstituted and wherein f and g are each independently an integer from 1 to 50 (e.g., 1 to 10, 1 to 5, 1 to 3 or 2 to 5). Substituted also includes a group that is substituted with one or more groups including, but not limited to, the following groups: fluoro, chloro, bromo, iodo, amino, amido, alkyl, hydroxy, alkoxy, alkylamido, alkenyl, alkynyl, alkoxycarbonyl, acyl, formyl, arylcarbonyl, aryloxycarbonyl, aryloxy, carboxy, haloalkyl, hydroxy, cyano, nitroso, nitro, azido, trifluoromethyl, trifluoromethoxy, thio, alkylthio, arylthiol, alkylsulfonyl, alkylsulfinyl, dialkylaminosulfonyl, sulfonic acid, carboxylic acid, dialkylamino and dialkylamido. Where there are two or more adjacent substituents, the substituents can be linked to form a carbocyclic or heterocyclic ring. Such adjacent groups can have a vicinal or germinal relationship, or they can be adjacent on a ring in, e.g., an ortho-arrangement. Each instance of substituted is understood to be independent. For example, a substituted aryl can be substituted with bromo and a substituted heterocycle on the same compound can be substituted with alkyl. It is envisaged that a substituted group can be substituted with one or more non-fluoro groups. As another example, a substituted group can be substituted with one or more non-cyano groups. As another example, a substituted group can be substituted with one or more groups other than haloalkyl. As yet another example, a substituted group can be substituted with one or more groups other than tert-butyl. As yet a further example, a substituted group can be substituted with one or more groups other than trifluoromethyl. As yet even further examples, a substituted group can be substituted with one or more groups other than nitro, other than methyl, other than methoxymethyl, other than dialkylaminosulfonyl, other than bromo, other than chloro, other than amido, other than halo, other than benzodioxepinyl, other than polycyclic heterocyclyl, other than polycyclic substituted aryl, other than methoxycarbonyl, other than alkoxycarbonyl, other than thiophenyl, or other than nitrophenyl, or groups meeting a combination of such descriptions. Further, substituted is also understood to include fluoro, cyano, haloalkyl, tert-butyl, trifluoromethyl, nitro, methyl, methoxymethyl, dialkylaminosulfonyl, bromo, chloro, amido, halo, benzodioxepinyl, polycyclic heterocyclyl, polycyclic substituted aryl, methoxy carbonyl, alkoxycarbonyl, thiophenyl, and nitrophenyl groups.
A variety of enzymes can be used to convert the substrates into useful products. Examples of enzymes that can be used include terpene synthases. For example, the enzymes employed can be those that naturally convert geranylgeranyl diphosphate (GGPP) into biosynthesis of gibberellins, carotenoids, chlorophylls, isoprenoid quinones, and geranylgeranylated proteins. However, the enzymes are also promiscuous and can accept unnatural substrates such as the unnatural GGPP analogs or derivatives described herein. Additional enzymes can also be employed that convert the products formed from the unnatural substrates (e.g., the primary products) into other products (e.g., secondary products).
For example, the enzymes can be from organisms such as Tripterygium wilfordii (Tw), Euphorbia peplus (Ep), Coleus forskohlii (Cf), Ajuga reptans (Ar), Perovskia atriciplifolia (Pa), Nepeta mussini (Nm), Origanum majorana (Om), Hyptis suaveolens (Hs), Grindelia robusta (Gr), Leonotis leonurus (Ll), Marrubium vulgare (Mv), Vitex agnus-castus (Vac), Euphorbia peplus (Ep), Ricinus communis (Rc), Daphne genkwa (Dg), Zea mays (Zm), and other organisms.
The enzymes can in some cases, for example, be type I or type II enzymes. In general, a type II enzyme can catalyze transformation of an unnatural substrate derivative of geranylgeranyl diphosphate (GGPP) to a primary terpene product, while the type I enzymes can modify such a terpene product to generate a second terpene product.
The enzymes can be used in single step reactions, or in multi-step reactions when mixed together or when used sequentially. Multi-step reactions can occur by enzyme coupling. Enzyme coupling refers to one enzyme catalyzing a reaction to produce a product that is a substrate for a second enzyme. For example, the type II and type I enzymes can be coupled together, where a type II enzyme can accept and enzymatically convert an unnatural substrate to a first product and where a type I enzyme accepts the first product as a substrate for enzymatic conversion to generate a second product. Such enzyme coupling is demonstrated in the Examples. In some cases, an unnatural substrate can undergo efficient conversion to a first product by one enzyme without producing side products or undesirable fragments that could undermine the efficiency of a second enzyme to produce desirable yields of a second product.
Examples of enzymes that can be used include those that naturally produce ent-CPP (e.g., TwTPS3, EpTPS7, ZmAN2), shown below.
Examples of enzymes that can be used include those that naturally produce (+)-CPP (e.g., CfTPS1, ArTPS1, PaTPS1, NmTPS1, OmTPS1, TwTPS9 and CfTPS16), shown below.
Examples of enzymes that can be used include those that naturally produce (13E)-labda-7,13-dien-15-yl diphosphate (i.e., (7,13)-LPP) (e.g., HsTPS1, GrTPS), shown below.
Examples of enzymes that can be used include those that naturally produce peregrinol diphosphate (PGPP) (e.g., LlTPS1, MvCPS1, VacTPS1), shown below.
Examples of enzymes that can be used include those that naturally produce (−)-kolavenyl diphosphate (KPP) (e.g., TwTPS10, TwTPS14, VacTPS5), shown below.
Examples of enzymes that can be used include those that naturally produce casbene (e.g., EpCBS, RcCBS, DgTPS1), shown below.
Approximately 30 functional diTPS of the mint family have been identified and isolated by the inventors as having both labdane-type and irregular diterpene biosynthetic activities. These enzymes represent a repository of enzymes that can be used in the methods and reaction mixtures described herein.
For example, an Ajuga reptans miltiradiene synthase (ArTPS3), a Leonotis leonurus sandaracopimaradiene synthase (L1TPS4), a Mentha spicata class I diterpene synthase (MsTPS1), an Origanum majorana trans-abienol synthase (OmTPS3), an Origanum majorana manool synthase (OmTPS4), an Origanum majorana palustradiene synthase (OmTPS5), Perovskia atriplicifolia miltiradiene synthase (PaTPS3), Prunella vulgaris miltiradiene synthase (PvTPS1), Salvia officinalis miltiradiene synthase (SoTPS1) were identified and isolated.
Eight of these enzymes, ArTPS3, L1TPS4, MsTPS1, OmTPS4, OmTPS5, PaTPS3, PvTPS1, and SoTPS1 can convert a labda-13-en-8-ol diphosphate ((+) LPP) [compound 10]) to 13R-(+)-manoyl oxide [8].
The ArTPS3, L1TPS4, OmTPS4, OmTPS5, PaTPS3, PvTPS1, and SoYPS1 enzymes can also convert peregrinol diphosphate (PgPP) [5] to a combination of compounds 1, 2, and 3, as illustrated below.
However, MsTPS1 produced only compound 3 from compound 5, while the OmTPS3 enzyme produced only 1, and 2. The OmTPS4 enzyme produced compound 4 (shown below) in addition to compounds 1, 2, and 3.
The ArTPS3, PaTPS3, PvTPS1, and SoTPS1 enzymes can also convert (+)-copalyl diphosphate ((+)-CPP) [31]) to miltiradiene [32].
However, LlTPS4 and MsTPS1 converted (+)-copalyl diphosphate ((+)-CPP) [31]) to sadaracopimaradiene [27], while OmTPS3 converted (+)-copalyl diphosphate ((+)-CPP) [31]) to trans-biformene [34].
The Ajuga reptans miltiradiene synthase (ArTPS3) has the amino acid sequence shown below (SEQ ID NO:1).
A nucleic acid encoding the Ajuga reptans miltiradiene synthase (ArTPS3) with SEQ ID NO:1 is shown below as SEQ ID NO:2.
The Leonotis leonurus sandaracopimaradiene synthase (L1TPS4) has the amino acid sequence shown below (SEQ ID NO:3).
A nucleic acid encoding the Leonotis leonurus sandaracopimaradiene synthase (L1TPS4) with SEQ ID NO:3 is shown below as SEQ ID NO:4.
The Mentha spicata class I diterpene synthase (MsTPS1) has the amino acid sequence shown below (SEQ ID NO:5).
A nucleic acid encoding the Mentha spicata class I diterpene synthase (MsTPS1) with SEQ ID NO:5 is shown below as SEQ ID NO:6.
A Nepeta mussinii ent-kaurene synthase (NmTPS2) was identified and isolated. This NmTPS2 enzyme was identified as an ent-kaurene synthase, which converts ent-CPP [16] into ent-kaurene [19].
The Nepeta mussinii ent-kaurene synthase (NmTPS2) has the amino acid sequence shown below (SEQ ID NO:7).
A nucleic acid encoding the Nepeta mussinii ent-kaurene synthase (NmTPS2) with SEQ ID NO:7 is shown below as SEQ ID NO:8.
An Origanum majorana trans-abienol synthase (OmTPS3) was identified and isolated. When this OmTPS3 enzyme was expressed in N. benthamiana with Hyptis suaveolens labda-7,13E-dienyl diphosphate synthase (HsTPS1) a new compound, labda-7,12E,14-triene [24], was produced. The HsTPS1 enzyme produced labda-7,13(16),14-triene [22] when HsTPS1 was expressed in N. benthamiana.
OmTPS3 also produced trans-abienol [11] from labda-13-en-8-ol diphosphate ((+)-8-LPP) [10]).
The Origanum majorana trans-abienol synthase (OmTPS3) has the amino acid sequence shown below (SEQ ID NO:9).
A nucleic acid encoding the Origanum majorana trans-abienol synthase (OmTPS3) with SEQ ID NO:9 is shown below as SEQ ID NO:10.
The Origanum majorana manool synthase (OmTPS4) can also convert ent-copalyl diphosphate (ent-CPP) [16] to ent-manool [20].
In addition, Origanum majorana manool synthase (OmTPS4) can also convert (+)-copalyl diphosphate ((+)-CPP) [31]) to manool [33].
The Origanum majorana manool synthase (OmTPS4) can have the amino acid sequence shown below (SEQ ID NO:11).
A nucleic acid encoding Origanum majorana manool synthase (OmTPS4) with SEQ ID NO:11 is shown below as SEQ ID NO:12.
Origanum majorana palustradiene synthase (OmTPS5) can also convert (+)-copalyl diphosphate ((+)-CPP) [M]) to palustradiene [29].
The Origanum majorana palustradiene synthase (OmTPS5) can have the amino acid sequence shown below (SEQ ID NO:13).
A nucleic acid encoding the Origanum majorana palustradiene synthase (OmTPS5) with SEQ ID NO:13 is shown below as SEQ ID NO:14.
The Perovskia atriplicifolia miltiradiene synthase (PaTPS3) can have the amino acid sequence shown below (SEQ ID NO:15).
A nucleic acid encoding the Perovskia atriplicifolia miltiradiene synthase (PaTPS3) with SEQ ID NO:15 is shown below as SEQ ID NO:16.
A Perovskia atriplicifolia miltiradiene synthase (PaTPS1) can have the amino acid sequence shown below (SEQ ID NO:17).
A nucleic acid encoding the Perovskia atriplicifolia miltiradiene synthase (PaTPS1) with SEQ ID NO:17 is shown below as SEQ ID NO:18.
The Salvia officinalis miltiradiene synthase (SoTPS1) can have the amino acid sequence shown below (SEQ ID NO:19).
A nucleic acid encoding the Salvia officinalis miltiradiene synthase (SoTPS1) with SEQ ID NO:19 is shown below as SEQ ID NO:20.
Ajuga reptans (+)-copalyl diphosphate synthase (ArTPS1) is a (+)-copalyl diphosphate ((+)-CPP) [31] synthase, and compound 31 is shown below.
The Ajuga reptans (+)-copalyl diphosphate synthase (ArTPS1) can have the amino acid sequence shown below (SEQ ID NO:21).
A nucleic acid encoding the Ajuga reptans (+)-copalyl diphosphate synthase (ArTPS1) with SEQ ID NO:21 is shown below as SEQ ID NO:22.
Ajuga reptans cleroda-4(18),13E-dienyl diphosphate synthase (ArTPS2) was identified and isolated. ArTPS2 was identified as a (5R,8R,9S,10R) neo-cleroda-4(18),13E-dienyl diphosphate [38] synthase. In addition, the combination of ArTPS2 and SsSS enzymes generated neo-cleroda-4(18),14-dien-13-ol [37]. These compounds are shown below.
ArTPS2 is of particular interest for applications in agricultural biotechnology, for example, because it is useful for production of neo-clerodane diterpenoids. Neo-clerodane diterpenoids, particularly those with an epoxide moiety at the 4(18) position, have garnered significant attention for their ability to deter insect herbivores (Coll et al., Phytochem Rev 7(1):25 (2008); Klein Gebbinck et al. Phytochemistry 61(7):737-770 (2002); Li et al. Nat Prod Rep 33(10):1166-1226 (2016)). The 4(18)-desaturated products produced by ArTPS2 (e.g., compounds 37 and 38 with the ═CH2 4(18) desaturation projecting from the A ring) the can be used in biosynthetic or semisynthetic routes to yield potent insect antifeedants.
The Ajuga reptans cleroda-4(18),13E-dienyl diphosphate synthase (ArTPS2) can have the amino acid sequence shown below (SEQ ID NO:23).
A nucleic acid encoding the Ajuga reptans cleroda-4(18),13E-dienyl diphosphate synthase (ArTPS2) with SEQ ID NO:23 is shown below as SEQ ID NO:24.
The Plectranthus barbatus (+)-Copalyl diphosphate synthase (CfTPS16) was identified and isolated using the methods described herein, and this CfTPS116 protein can have the amino acid sequence shown below (SEQ ID NO:25).
A nucleic acid encoding the Plectranthus barbatus (+)-Copalyl diphosphate synthase (CfTPS16) with SEQ ID NO:25 is shown below as SEQ ID NO:26.
Hyptis suaveolens labda-7,13E-dienyl diphosphate synthase (HsTPS1) was identified and isolated, and is a (5S, 9S, 10S) labda-7,13E-dienyl diphosphate [21] synthase. When HsTPS1 was expressed in N. benthamiana, labda-7,13(16),14-triene [22] was formed. The combination of HsTPS1 with OmTPS3 produced labda-7,12E,14-triene [24].
The Hyptis suaveolens labda-7,13E-dienyl diphosphate synthase (HsTPS1) can have the amino acid sequence shown below (SEQ ID NO:27).
A nucleic acid encoding the Hyptis suaveolens labda-7,13E-dienyl diphosphate synthase (HsTPS1) with SEQ ID NO:27 is shown below as SEQ ID NO:28.
Leonotis leonurus peregrinol diphosphate synthase (L1TPS1) was identified and isolated using the methods described herein. The LlTPS1 enzyme was identified as a peregrinol diphosphate (PgPP) [5] synthase, where the peregrinol diphosphate (PgPP) [5] compound is shown below.
The Leonotis leonurus peregrinol diphosphate synthase (L1TPS1) can have the amino acid sequence shown below (SEQ ID NO:29).
A nucleic acid encoding the Leonotis leonurus peregrinol diphosphate synthase (L1TPS1) with SEQ ID NO:29 is shown below as SEQ ID NO:30.
Nepeta mussinii (+)-copalyl diphosphate synthase (NmTPS1) was identified and isolated. The NmTPS1 enzyme can synthesize compound 31, shown below.
The Nepeta mussinii (+)-copalyl diphosphate synthase (NmTPS1) can have the amino acid sequence shown below (SEQ ID NO:31).
A nucleic acid encoding the Nepeta mussinii (+)-copalyl diphosphate synthase (NmTPS1) with SEQ ID NO:31 is shown below as SEQ ID NO:32.
Origanum majorana (+)-copalyl diphosphate synthase (OmTPS1) was identified and isolated as describe herein. The OmTPS1 enzyme can synthesize compound 31. OmTPS1 can also synthesize palustradiene [29] (shown below), when combined with OmTPS5.
The Origanum majorana (+)-copalyl diphosphate synthase (OmTPS1) can have the amino acid sequence shown below (SEQ ID NO:33).
A nucleic acid encoding the Origanum majorana (+)-copalyl diphosphate synthase (OmTPS1) with SEQ ID NO:33 is shown below as SEQ ID NO:34.
A Perovskia atriplicifolia (+)-Copalyl diphosphate synthase (PaTPS1) enzyme was identified and isolated. This Perovskia atriplicifolia (+)-Copalyl diphosphate synthase (PaTPS1) enzyme was identified to be a (+)-copalyl diphosphate ((+)-CPP) synthase that can synthesize compound 31. The Perovskia atriplicifolia (+)-Copalyl diphosphate synthase (PaTPS1) can have the amino acid sequence shown below (SEQ ID NO:35).
A nucleic acid encoding the Perovskia atriplicifolia (+)-Copalyl diphosphate synthase (PaTPS1) enzyme with SEQ ID NO:35 is shown below as SEQ ID NO:36.
Pogostemon cablin (10R)-labda-8,13E-dienyl diphosphate synthase (PcTPS1) was identified and isolated. This Pogostemon cablin (10R)-labda-8,13E-dienyl diphosphate synthase (PcTPS1) enzyme was identified to be a (10R)-labda-8,13E-dienyl diphosphate synthase, which can synthesize compound 25.
The combination of PcTPS1 and SsSS, both in-vitro, and in N. benthamiana expression produced (10R)-labda-8,14-en-13-ol [26], shown below.
This Pogostemon cablin (10R)-labda-8,13E-dienyl diphosphate synthase (PcTPS1) can have the amino acid sequence shown below (SEQ ID NO:37).
A nucleic acid encoding the Pogostemon cablin (10R)-labda-8,13E-dienyl diphosphate synthase (PcTPS1) enzyme with SEQ ID NO:37 is shown below as SEQ ID NO:38.
Prunella vulgaris 11-hydroxy vulgarisane synthase (PvHVS) was identified and isolated. The Prunella vulgaris 11-hydroxy vulgarisane synthase (PvHVS) enzyme catalyzes the first committed step and forms the scaffold found in all Vulgarisins, a class of diterpenes with pharmaceutical applications (e.g., gout, cancer). For example, PvHVS can synthesize 11-hydroxy vulgarisane (shown below).
An example of a formula for several Vulgarisin diterpenes is shown below.
Vulgarisins B (1) and C (2) exhibit modest cytotoxicity activity against human lung carcinoma A549 cell line (Lou et al. Tetrahedron Letters 58: 401-404 (2017)).
The Prunella vulgaris 11-hydroxy vulgarisane synthase (PvHVS) can have the amino acid sequence shown below (SEQ ID NO:39).
A nucleic acid encoding the i Prunella vulgaris 11-hydroxy vulgarisane synthase (PvHVS) enzyme with SEQ ID NO:39 is shown below as SEQ ID NO:40.
A Chiococca alba ent-CPP synthase (CaTPS1) was identified and isolated. This CaTPS1 enzyme was identified that converts GGPP to ent-CPP [16].
The Chiococca alba ent-CPP synthase (CaTPS1) has the amino acid sequence shown below (SEQ ID NO:41).
A nucleic acid encoding the Chiococca alba ent-CPP synthase (CaTPS1) with SEQ ID NO:41 is shown below as SEQ ID NO:42.
A Chiococca alba (5R,8S,9S,10S)-labda-13-en-8-ol diphosphate (ent-8-LPP) synthase (CaTPS2) was identified and isolated. This CaTPS2 enzyme was identified as an 5R,8S,9S,10S)-labda-13-en-8-ol diphosphate (ent-8-LPP) synthase, which converts GGPP to 5R,8S,9S,10S)-labda-13-en-8-ol diphosphate (ent-8-LPP, [7]).
The Chiococca alba (5R,8S,9S,10S)-labda-13-en-8-ol diphosphate (ent-8-LPP) synthase (CaTPS2) has the amino acid sequence shown below (SEQ ID NO:43).
A nucleic acid encoding the Chiococca alba (5R,8S,9S,10S)-labda-13-en-8-ol diphosphate (ent-8-LPP) synthase (CaTPS2) with SEQ ID NO:43 is shown below as SEQ ID NO:44.
A Chiococca alba CaTPS3 and CaTPS4 were identified and isolated. CaTPS3 and CaTPS4 were identified as an ent-kaurene synthase, converting ent-CPP [16] into ent-kaurene [19].
The Chiococca alba ent-kaurene synthase (CaTPS3) has the amino acid sequence shown below (SEQ ID NO:45).
A nucleic acid encoding the Chiococca alba ent-kaurene synthase (CaTPS3) with SEQ ID NO:45 is shown below as SEQ ID NO:46.
The Chiococca alba ent-kaurene synthase (CaTPS4) has the amino acid sequence shown below (SEQ ID NO:47).
A nucleic acid encoding the Chiococca alba ent-kaurene synthase (CaTPS4) with SEQ ID NO:47 is shown below as SEQ ID NO:48.
A Chiococca alba 13(R)-epi-dolabradiene synthase (CaTPS5) was identified and isolated. This CaTPS5 enzyme was identified as an 13(R)-epi-dolabradiene synthase, which converts ent-CPP [16] to 13(R)-epi-dolabradiene.
The Chiococca alba 13(R)-epi-dolabradiene synthase (CaTPS5) has the amino acid sequence shown below (SEQ ID NO:49).
A nucleic acid encoding the Chiococca alba 13(R)-epi-dolabradiene synthase (CaTPS5) with SEQ ID NO:49 is shown below as SEQ ID NO:50.
A Salvia hispanica (−)-kolavenyl diphosphate synthase (ShTPS1) was identified and isolated. This ShTPS1 enzyme was identified as an (−)-kolavenyl 35 diphosphate synthase, which converts GGPP to (−)-kolavenyl diphosphate [36].
The Salvia hispanica (−)-kolavenyl diphosphate synthase (ShTPS1) has, for example, an amino acid sequence shown below (SEQ ID NO:51).
A nucleic acid encoding the Salvia hispanica (−)-kolavenyl diphosphate synthase (ShTPS1) with SEQ ID NO:51 is shown below as SEQ ID NO:52.
A Teucrium canadense cleroda-4(18),13E-dienyl diphosphate synthase (TcTPS1) was identified and isolated. This TcTPS1 enzyme was identified as a cleroda-4(18),13E-dienyl diphosphate synthase, which converts GGPP to cleroda-4(18),13E-dienyl diphosphate [38]. In addition, the combination of TcTPS1 and SsSS enzymes generated neo-cleroda-4(18),14-dien-13-ol [37]. These compounds are shown below.
5 The Teucrium canadense cleroda-4(18),13E-dienyl diphosphate synthase (TcTPS1) amino acid sequence is shown below as SEQ ID NO:53.
A nucleic acid encoding the Teucrium canadense Cleroda-4(18),13E-dienyl diphosphate synthase (TcTPS1) has with SEQ ID NO:53 is shown below as SEQ ID NO:54.
Salvia officinalis (SoTPS2), Scutellaria baicalensis SbTPS1, and SbTPS2 enzymes were identified and isolated. These SoTPS2, SbTPS1, SbTPS2, CfTPS18a and CfTPS18b enzymes were all identified as ent-CPP synthases, which convert GGPP to ent-CPP.
The Salvia officinalis (SoTPS2) enzyme can have the amino acid sequence shown below (SEQ ID NO:55).
A nucleic acid encoding the Salvia officinalis (SoTPS2) has with SEQ ID NO:55 is shown below as SEQ ID NO:56.
A Scutellaria baicalensis SbTPS1 amino acid sequence shown below (SEQ ID NO:57).
A nucleic acid encoding the Scutellaria baicalensis SbTPS1 with SEQ ID NO:57 is shown below as SEQ ID NO:58.
A Scutellaria baicalensis SbTPS2 amino acid sequence is shown below (SEQ ID NO:59)
A nucleic acid encoding the Scutellaria baicalensis SbTPS2 with SEQ ID NO:59 is shown below as SEQ ID NO:60.
An example of a Salvia sclarea sclareol synthase amino acid sequence is shown below (SEQ ID NO:61; NCBI accession no. AET21246.1).
A nucleic acid encoding the Salvia sclarea sclareol synthase with SEQ ID NO:61 is shown below as SEQ ID NO:62.
An example of a Marrubium vulgare (Mv) CPS1 amino acid sequence is shown below (SEQ ID NO:63).
An example of a Marrubium vulgare (Mv) TPS5 (syn. MvELS) amino acid sequence is shown below (SEQ ID NO:64).
An example of a Kitasatospora griseola TPS2 (KgTPS2) amino acid sequence is shown below (SEQ ID NO:65).
An example of an Origanum majorana TPS1 (0mTPS1) amino acid sequence is shown below (SEQ ID NO:66).
An example of an Origanum majorana TPS4 (OmTPS4) amino acid sequence is shown below (SEQ ID NO:67).
The inventors have described a CYP71D381 from C. forskohlii, which resulted in oxidized derivatives at alternative positions outside the known forskolin chemistry (Pateraki et al. Elife 6 (2017)). The sequence for the CYP71D381 from Plectranthus barbatus is shown below (SEQ ID NO:68).
Mining of nearly 50 transcriptomes of related members of the mint family (Lamiaceae; Johnson et al., J. Biol. Chem. 294: 1349-1362 (2019)) indicates that the mint family provides rich repository of members of the CYP71D and CYP76AH enzymes (over 200 candidates, functional characterization, preliminary results by the inventors). Any of these enzymes can be used for additional/alternative oxidation chemistries to produce useful products.
The cyclization of diterpenes is among the most complex reactions found in nature. Typically, more than half of the carbons of GGPP undergo changes in connection, hybridization (sp-status), and stereochemistry during the carbocationic cascade. Stabilized in the active site of diterpene synthases, those carbocation intermediates undergo electron delocalization, hydride and alkyl-shifts, and can be quenched by access to water. For example, predicted cyclization reactions for conversion of GGPP to hydroxy-vulgarisane are shown below.
The inventors have recently discovered the PvHVS enzyme (SEQ ID NO:40), which can generate the irregular diterpene founding the class of bioactive vulgarisane compounds in Prunella vulgaris (see Pelot et al. Plant Physiol. 178: 54 LP-71 (2018)).
Mutated variants of diTPS can be deployed for diversification of the enzymes to increase the range of products produced, for example, by controlling the stereochemistry of the product outcome. Previously, generation of individual compounds from GGPP remained limited to the natural C20 chemical space of diterpenes (Schulte et al. Biochemistry 57: 3473-3479 (2018)). Terpene cyclization has been investigated through crystallography, structural modelling and mutagenesis studies including unreactive fluorinated, azaisoprenyl or thioloisoprenyl diphosphate analogs, by quantum-chemical calculations of intermediates, and by isotopically labelled natural precursors. With exceptions, the majority of approaches are static (non-dynamic) and have not yet been applied to terpenoid synthases, where reports are limited to single-enzyme-analog tests. Crystal structures for plant diTPS are similarly restricted to three enzymes only, the grand fir bifunctional class II/I abietadiene synthase, the class II Arabidopsis thaliana ent-CPS30, and the class I Taxus taxadiene synthase. Cyclization of rationally designed substrates with both altered spatial and electronic properties will provide a unique and dynamic facet by evaluation of the previously unrecognized substrate tolerance: steric constraints, stabilization of transition states and kinetics of the enzymes. With that, the proposed technology complements current tools exploring the mechanism of the cationic cascade of terpene cyclization. Structure-guided mutational studies for identified optimal modules, combined with the substrate tolerance described herein can broaden the accessible range of enzymes and products produced.
Enzymes that exhibit the following characteristics are generally preferred for use in methods of producing desirable products: (i) terpenoid synthases with high natural substrate tolerance, (ii) those generating a set of intermediates with maximized chemical diversity, and (iii) enzymes that provide intermediates in the pathways to forskolin and jolkinol C (P450s, ADHs, ACTs). In some cases, the enzymes can be active as recombinant enzymes in E. coli and/or the enzymes have demonstrated functionally in yeast.
As one example of an enzyme that can accept multiple unnatural substrates is CfTps2, which the inventors have demonstrated has such useful activity. The CfTps2 enzyme can provide the first step in synthesis of the cardiac stimulant and cognition enhancer forskolin which is derived from Coleus forskohiii. The CfTps2 enzyme can also serve as the first step in production of sclareol, which is an industrial precursor for ambroxoid fragrance substances. The ability to modify, in a targeted manner, these biological active or industrially significant natural products would facilitate the design, testing, and production of novel materials and biologically active agents.
Enzymes described herein can therefore have one or more deletions, insertions, replacements, or substitutions in a part of the enzyme. The enzyme(s) described herein can have, for example, at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 93%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99% sequence identity to a sequence described herein.
In some cases, enzymes can have conservative changes such as one or more deletions, insertions, replacements, or substitutions that have no significant effect on the activities of the enzymes. Examples of conservative substitutions are provided below in Table IA.
The enzymes can also include a tag, for example, as a label or to facilitate purification of the enzyme. Examples of such tags include histidine tags, streptavidin tags, biotin tags, antibody fragments, and the like.
Terpenes, including diterpenes and terpenoids, can be made in a variety of host organisms in vivo. In some cases, the enzymes described herein can be made in host cells, and those enzymes can be extracted from the host cells for use in vitro. As used herein, a “host” means a cell, tissue or organism capable of replication. The host can have an expression cassette or expression vector that can include a nucleic acid segment encoding an enzyme that is involved in the biosynthesis of terpenes.
The term “host cell”, as used herein, refers to any prokaryotic or eukaryotic cell that can be transformed with an expression cassettes or vector carrying the nucleic acid segment encoding an enzyme that is involved in the biosynthesis of one or more terpenes or terpenoids. The host cells can, for example, be a plant, bacterial, insect, or yeast cell. Expression cassettes encoding biosynthetic enzymes can be incorporated or transferred into a host cell to facilitate manufacture of the enzymes described herein or the terpene, diterpene, or terpenoid products of those enzymes. The host cells can be present in an organism. For example, the host cells can be present in a host such as a microorganism, fungus, or plant.
Also described herein are expression systems that include at least one expression cassette (e.g., expression vectors or transgenes) that encode one or more of the enzyme(s) described herein. For example, the expression systems can also include one or more expression cassettes any of the monoterpene synthase, diterpene synthase, sesquiterpene synthase, sesterterpene synthase, triterpene synthase, tetraterpene synthase, polyterpene synthase, transcription factor, cytochrome P450, cytochrome P450 reductase, 1-deoxy-D-xylulose 5-phosphate synthase (DXS), 1-deoxy-D-xylulose 5-phosphate-reducto-isomerase, cytidine 5′-diphosphate-methylerythritol (CDP-ME) synthetase (IspD), 2-C-methyl-d-erythritol 2,4-cyclodiphosphate synthase (IspF), HMG-CoA synthase, HMG-CoA reductase (HMGR), mevalonic acid kinase (MVK), phosphomevalonate kinase (PMK), mevalonate-5-diphosphate decarboxylase (MPD), isopentenyl diphosphate isomerase, abietadiene synthase (ABS), farnesylpyrophosphate synthase (FPPS), or squalene synthase (SQS), LDSP-protein fusions, or enzymes that facilitate production of terpenoids, terpene precursors, terpene building blocks, or products derived from terpenoids.
Nucleic acids encoding the enzymes can have sequence modifications. For example, nucleic acid sequences described herein can be modified to more optimally express the enzymes. Hence, the nucleic acid segment encoding the enzymes can be optimized to improve expression in different host cells. Most amino acids can be encoded by more than one codon, but when an amino acid is encoded by more than one codon, the codons are referred to as degenerate codons. A listing of degenerate codons is provided in Table 1B below.
Different organisms may translate different codons more or less efficiently (e.g., because they have different ratios of tRNAs) than other organisms. Hence, when some amino acids can be encoded by several codons, a nucleic acid segment can be designed to optimize the efficiency of expression of an enzyme by using codons that are preferred by an organism of interest. For example, the nucleotide coding regions of the enzymes described herein can be codon optimized for expression in various microorganisms, fungi, or plant species.
An optimized nucleic acid can have less than 100%, less than 99%, less than 98%, less than 97%, less than 95%, or less than 94%, or less than 93%, or less than 92%, or less than 91%, or less than 90%, or less than 89%, or less than 88%, or less than 85%, or less than 83%, or less than 80%, or less than 75% nucleic acid sequence identity to a corresponding non-optimized (e.g., a non-optimized parental or wild type enzyme nucleic acid) sequence. Nucleic acid segment(s) encoding one or more enzyme(s) can therefore have one or more nucleotide deletions, insertions, replacements, or substitutions.
The nucleic acid segments encoding one or more enzyme can be operably linked to a promoter, which provides for expression of mRNA from the nucleic acid segments. The promoter is typically a promoter functional in a microorganism, fungus or plant. A nucleic acid segment encoding one or more enzyme is operably linked to the promoter, for example, when it is located downstream from the promoter. The combination of a coding region for an enzyme operably linked to a promoter forms an expression cassette, which can include other elements and regulatory sequences as well.
Promoter regions are typically found in the flanking DNA upstream from the coding sequence in both the prokaryotic and eukaryotic cells. A promoter sequence provides for regulation of transcription of the downstream gene sequence and typically includes from about 50 to about 2,000 nucleotide base pairs. Promoter sequences can also contain regulatory sequences such as enhancer sequences that can influence the level of gene expression. Some isolated promoter sequences can provide for gene expression of heterologous DNAs, that is a DNA different from the native or homologous DNA.
Promoter sequences are also known to be strong or weak, or inducible. A strong promoter provides for a high level of gene expression, whereas a weak promoter provides for a very low level of gene expression. An inducible promoter is a promoter that provides for the turning on and off of gene expression in response to an exogenously added agent, or to an environmental or developmental stimulus. For example, a bacterial promoter such as the Ptac promoter can be induced to varying levels of gene expression depending on the level of isopropyl-beta-D-thiogalactoside added to the transformed cells. Promoters can also provide for tissue specific or developmental regulation. An isolated promoter sequence that is a strong promoter for heterologous DNAs is often advantageous because it provides for a sufficient level of gene expression for easy detection and selection of transformed cells and provides for a high level of gene expression when desired.
Examples of prokaryotic promoters that can be used include, but are not limited to, SP6, T7, T5, tac, bla, trp, gal, lac, or maltose promoters. Examples of eukaryotic promoters that can be used include, but are not limited to, constitutive promoters, e.g., viral promoters such as CMV, SV40 and RSV promoters, as well as regulatable promoters, e.g., an inducible or repressible promoter such as the tet promoter, the hsp70 promoter and a synthetic promoter regulated by CRE.
Examples of plant promoters include the CaMV 35S promoter (Odell et al., Nature. 313:810-812 (1985)), or others such as CaMV 19S (Lawton et al., Plant Molecular Biology. 9:315-324 (1987)), nos (Ebert et al., Proc. Natl. Acad. Sci. USA. 84:5745-5749 (1987)), Adhl (Walker et al., Proc. Natl. Acad. Sci. USA. 84:6624-6628 (1987)), sucrose synthase (Yang et al., Proc. Natl. Acad. Sci. USA. 87:4144-4148 (1990)), α-tubulin, ubiquitin, actin (Wang et al., Mol. Cell. Biol. 12:3399 (1992)), cab (Sullivan et al., Mol. Gen. Genet. 215:431 (1989)), PEPCase (Hudspeth et al., Plant Molecular Biology. 12:579-589 (1989)) or those associated with the R gene complex (Chandler et al., The Plant Cell. 1:1175-1183 (1989)). Further suitable promoters include a CYP71D16 trichome-specific promoter and the CBTS (cembratrienol synthase) promotor, cauliflower mosaic virus promoter, the Z10 promoter from a gene encoding a 10 kD zein protein, a Z27 promoter from a gene encoding a 27 kD zein protein, the plastid rRNA-operon (rrn) promoter, inducible promoters, such as the light inducible promoter derived from the pea rbcS gene (Coruzzi et al., EMBO J. 3:1671 (1971)), RUBISCO-SSU light inducible promoter (SSU) from tobacco and the actin promoter from rice (McElroy et al., The Plant Cell. 2:163-171 (1990)). Other promoters that are useful can also be employed.
Examples of leaf-specific promoters include the promoter from the Populus ribulose-1,5-bisphosphate carboxylase small subunit gene (Wang et al. Plant Molec Biol Reporter 31 (1): 120-127 (2013)), the promoter from the Brachypodium distachyon sedoheptulose-1,7-bisphosphatase (SBPase-p) gene (Alotaibi et al. Plants 7(2): 27 (2018)), the fructose-1,6-bisphosphate aldolase (FBPA-p) gene from Brachypodium distachyon (Alotaibi et al. Plants 7(2): 27 (2018)), and the photosystem-II promoter (CAB2-p) of the rice (Oryza sativa L.) light-harvest chlorophyll a/b binding protein (CAB) (Song et al. J Am Soc Hort Sci 132(4): 551-556 (2007)). Additional promoters that can be used include those available in expression databases, see for example, website bar.utoronto.ca/eplant/ which includes poplar or heterologous promoters from Arabidopsis (for example from AT2G26020/PDF1.2b or AT5G44420 / LCR77).
Alternatively, novel tissue specific promoter sequences may be employed. cDNA clones from a particular tissue can be isolated and those clones which are expressed specifically in that tissue can be identified, for example, using Northern blotting. Preferably, the gene isolated is not present in a high copy number but is relatively abundant in specific tissues. The promoter and control elements of corresponding genomic clones can then be localized using techniques well known to those of skill in the art.
Plant plastid originated promoters can also be used, for example, to improve expression in plastids, for example, a rice clp promoter, or tobacco rrn promoter. Chloroplast-specific promoters can also be utilized for targeting the foreign protein expression into chloroplasts. For example, the 16S ribosomal RNA promoter (Prrn) like psbA and atpA gene promoters can be used for chloroplast transformation.
A nucleic acid encoding one or more enzyme can be combined with the promoter by standard methods to yield an expression cassette, for example, as described in Sambrook et al. (MOLECULAR CLONING: A LABORATORY MANUAL. Second Edition (Cold Spring Harbor, NY: Cold Spring Harbor Press (1989); MOLECULAR CLONING: A LABORATORY MANUAL. Third Edition (Cold Spring Harbor, NY: Cold Spring Harbor Press (2000)). Briefly, a plasmid containing a promoter such as the 35S CaMV promoter or the CYP71D16 trichome-specific promoter can be constructed as described in Jefferson (Plant Molecular Biology Reporter 5:387-405 (1987)) or obtained from Clontech Lab in Palo Alto, California (e.g., pBI121 or pBI221). Typically, these plasmids are constructed to have multiple cloning sites having specificity for different restriction enzymes downstream from the promoter.
The expression cassette or vector can include nucleic acid sequence encoding a marker product. This marker product is used to determine if the gene has been delivered to the cell and once delivered is being expressed. Marker genes can include the E. coli lacZ gene which encodes β-galactosidase, and green fluorescent protein. In some embodiments the marker can be a selectable marker. When such selectable markers are successfully transferred into a host cell, the transformed host cell can survive if placed under selective pressure. There are two widely used distinct categories of selective regimes. The first category is based on a cell's metabolism and the use of a mutant cell line which lacks the ability to grow independent of a supplemented media. The second category is dominant selection which refers to a selection scheme used in any cell type and does not require the use of a mutant cell line. These schemes typically use a drug to arrest growth of a host cell. Those cells which have a novel gene would express a protein conveying drug resistance and would survive the selection. Examples of such dominant selection use the drugs neomycin (Southern P. and Berg, P., J. Molec. Appl. Genet. 1: 327 (1982)), mycophenolic acid, (Mulligan, R. C. and Berg, P. Science 209: 1422 (1980)) or hygromycin, (Sugden, B. et al., Mol. Cell. Biol. 5: 410-413 (1985)).
The expression cassettes can be within vectors such as plasmids, viral vectors, viral nucleic acids, phage nucleic acids, phages, cosmids, or artificial chromosomes.
Transfer of the expression cassettes or vectors into host cells can be by methods available in the art and readily adaptable for use in the method described herein. Expression cassettes and vectors can be incorporated into host cells, for example, calcium-mediated transformation, electroporation, microinjection, lipofection, particle bombardment, chemical transfectants, physico-mechanical methods such as electroporation, or direct diffusion of DNA.
In some cases, one or more enzyme cassettes can be introduced into a single host cell. Such transformed host cells can then be used either for producing one or more enzymes or for chemical conversion of an unnatural substrate into a useful terpene product.
After expression in a suitable host, in some cases the enzymes can be purified or semi-purified for use within in vitro enzyme catalyzed reactions to generate terpenes. For example, the host cells can be lysed, and the enzymes purified or semi-purified to the extent needed to reduce side reactions. Purification of the enzymes also removes cellular debris that can complicate purification of the terpene products of enzymatic reactions. Purification of the enzymes can include lysis of host cells, removal of cellular debris by centrifugation or precipitation, solubilization of proteins, column chromatography (e.g., size selection chromatography, ion exchange chromatography), retrieval of tagged enzymes using affinity chromatography, and combinations thereof. For example, in some cases the enzymes can be histidine-tagged and purified or semi-purified by Ni-NTA agarose or Ni-NTA columns.
Methods are described herein that are useful for synthesizing terpenoids and products made from terpenoids. The methods can involve contacting one or more of the substrates described herein with one or more enzymes capable of synthesizing at least one terpene to produce a terpenoid product. In some cases, the methods can involve incubating one or more of the substrates described herein with a population of host cells having a at least one heterologous expression cassette or expression vector that can express one or more enzymes capable of synthesizing at least one terpenoid product. The enzymes capable of synthesizing at least one terpenoid product can be referred to as a primary enzyme. The methods can also involve contacting the terpenoid product with a secondary enzyme that can modify the terpenoid product into another useful product.
For example, one method can involve contacting one or more of the substrates described herein with one or more enzymes capable of synthesizing at least one terpene to produce a terpenoid product.
For example, another method can involve (a) incubating a population of host cells or host tissue that includes one or more expression cassettes (or vectors) that have a promoter operably linked to a nucleic acid segment encoding an enzyme capable of synthesizing at least one terpene; and (b) isolating at least one terpenoid product from the population of host cells or the host tissue.
The enzymes can be any of the enzymes described herein. For example, the enzymes can be a monoterpene synthase, diterpene synthase, sesquiterpene synthase, sesterterpene synthase, triterpene synthase, tetraterpene synthase, or polyterpene synthase. Enzymes used for modifying a terpenoid product (e.g., secondary enzymes) can include one or more transcription factor, cytochrome P450, cytochrome P450 reductase, 1-deoxy-D-xylulose 5-phosphate synthase (DXS), 1-deoxy-D-xylulose 5-phosphate-reducto-isomerase, cytidine 5′-diphosphate-methylerythritol (CDP-ME) synthetase (IspD), 2-C-methyl-d-erythritol 2,4-cyclodiphosphate synthase (IspF), geranylgeranyl diphosphate synthase (GGDPS), HMG-CoA synthase, HMG-CoA reductase (HMGR), mevalonic acid kinase (MVK), phosphomevalonate kinase (PMK), mevalonate-5-diphosphate decarboxylase (MPD), isopentenyl diphosphate isomerase (IDI), abietadiene synthase (ABS), farnesylpyrophosphate synthase (FPPS), ribulose bisphosphate carboxylase, squalene synthase (SQS), patchoulol synthase, or WRI1 protein; and (b) isolating lipids from the population of host cells, the host plant's cells, or the host tissue. In some cases, a combination of enzymes, transcription factors, and lipid droplet proteins can be expressed in host cells, host plant, or host tissues.
As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Also, as used herein, “and/or” refers to, and encompasses, any and all possible combinations of one or more of the associated listed items. Unless otherwise defined, all terms, including technical and scientific terms used in the description, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
The term “about”, as used herein, can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range.
The term “enzyme” or “enzymes”, as used herein, refers to a protein catalyst capable of catalyzing a reaction. Herein, the term does not mean only an isolated enzyme, but also includes a host cell expressing that enzyme. Accordingly, the conversion of A to B by enzyme C should also be construed to encompass the conversion of A to B by a host cell expressing enzyme C. However, in some cases, purified or semi-purified enzymes are used to catalyze formation of terpenes within in vitro reactions.
The term “heterologous” when used in reference to a nucleic acid refers to a nucleic acid that has been manipulated in some way. For example, a heterologous nucleic acid includes a nucleic acid from one species introduced into another species. A heterologous nucleic acid also includes a nucleic acid native to an organism that has been altered in some way (e.g., mutated, added in multiple copies, linked to a non-native promoter or enhancer sequence, etc.). Heterologous nucleic acids can include cDNA forms of a nucleic acid; the cDNA may be expressed in either a sense (to produce mRNA) or anti-sense orientation (to produce an anti-sense RNA transcript that is complementary to the mRNA transcript). For example, heterologous nucleic acids can be distinguished from endogenous plant nucleic acids in that the heterologous nucleic acids are typically joined to nucleic acids comprising regulatory elements such as promoters that are not found naturally associated with the natural gene for the protein encoded by the heterologous gene. Heterologous nucleic acids can also be distinguished from endogenous plant nucleic acids in that the heterologous nucleic acids are in an unnatural chromosomal location or are associated with portions of the chromosome not found in nature (e.g., the heterologous nucleic acids are expressed in tissues where the gene is not normally expressed).
The terms “identical” or percent “identity”, as used herein, in the context of two or more nucleic acids or polypeptide sequences, refer to two or more sequences or subsequences that are the same or have a specified percentage of amino acid residues or nucleotides that are the same (e.g., 75% identity, 80% identity, 85% identity, 90% identity, 95% identity, 97% identity, 98% identity, 99% identity, or 100% identity in pairwise comparison). Sequence identity can be determined by comparison and/or alignment of sequences for maximum correspondence over a comparison window, or over a designated region as measured using a sequence comparison algorithm, or by manual alignment and visual inspection. The percentage is calculated by determining the number of positions at which the identical nucleic acid base or amino acid residue occurs in both sequences to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the window of comparison and multiplying the results by 100 to yield the percentage of sequence identity. A “reference sequence” is a defined sequence used as a basis for a sequence comparison; a reference sequence may be a subset of a larger sequence.
As used herein, a “native” nucleic acid or polypeptide means a DNA, RNA, or amino acid sequence or segment thereof that has not been manipulated in vitro, i.e., has not been isolated, purified, amplified and/or modified.
The terms “in operable combination,” “in operable order,” and “operably linked” refer to the linkage of nucleic acid sequences in such a manner that a nucleic acid molecule capable of directing the transcription of a coding region (e.g., gene) and/or the synthesis of a desired protein molecule is produced. The term also refers to the linkage of amino acid sequences in such a manner so that a functional protein is produced.
As used herein the term “terpene” includes any type of terpene or terpenoid, including for example any monoterpene, diterpene, sesquiterpene, sesterterpene, triterpene, tetraterpene, polyterpene, and any mixture thereof.
As used herein, the term “wild-type” when made in reference to a gene refers to a functional gene common throughout an outbred population. As used herein, the term “wild-type” when made in reference to a gene product refers to a functional gene product common throughout an outbred population. A functional wild-type gene is that which is most frequently observed in a population and is thus arbitrarily designated the “normal” or “wild-type” form of the gene.
The following Examples illustrate some of the experimental work involved in development of the invention.
This Example summarizes methods that include synthesizing and screening an inventory of unnatural substrates producing novel decalin-core diphosphate intermediates and irregular terpene-like products. Preliminary results indicate that novel, structurally diverse unnatural diterpene substrates, mimicking the natural precursor, are accessible and can be processed to produce unnatural terpenes.
Initially, a panel of substrates with altered carbon number, inserted heteroatoms and rearranged linear and branched structures will be prepared. Class II diterpene synthases (diTPS) produce a characteristic decalin core intermediate. Screens are performed of functionally distinct class II diTPS enzymes with a panel of substrates (
Many class I diTPS of the decalin-core diterpene biosynthesis accept a range of class II intermediates, producing diverse products. The inventors have selected promiscuous class I diTPS and will examine their substrate tolerance against the unnatural class II intermediates. Products formed, for example as illustrated in
Modular pairs of diterpene synthases forming decalin core scaffolds were assembled through combinatorial biochemistry into new-to-nature pathways, yielding regioselective and stereoselective access to a panel of over 50 diterpene scaffolds, including novel compounds and those previously inaccessible. P450 enzymes were found to catalyze oxygenations of multiple substrates not native to the pathways and could also be substituted by enzymes from other species. Hence, our current repertoire of diTPS gives access to an estimated 75 scaffolds, while P450s, ACTs and ADHs can further modify each scaffold leading to an at least ten-fold diversification of possible diterpene pathways (see
A prototype pipeline was developed to generate chemically diversified and naturally inspired small molecules of the diterpene class at unprecedented chemical diversity (see
Over a dozen unnatural GGPP substrates were developed. The test-learn-design cycle informs further structural refinement of substrates, bringing the anticipated number to approximately 100 compounds. With its inherent building block principle, this strategy will be invaluable for high-throughput development of similar substrates for other classes of terpenoids and the resulting library of substrates will serve as a screening tool for future studies against an ever-expanding number of isolated enzymes.
This Example describes preparation of a library of unnatural isoprenyl-diphosphate derivatized substrates and screening a panel of class II labdane-type and class I macrocyclic, irregular-type diterpene synthases to advance mechanistic and structural understanding of the cationic cyclization cascades of these enzymes and to produce a collection of novel unnatural small molecules.
The diversity of substrates is synthetically explored that can be tolerated by the inventors' expansive toolbox of class II and I diterpene synthases (diTPS). Initial findings will provide key data guiding more extensive investigation of features that influence the cationic cyclization cascade and an understanding of substrate features that are tolerated, to generate a wide diversity of previously unknown products. The goal is to prepare unnatural products using a diversity of structural motifs that would, upon cyclization generate novel structures. These cyclization precursors will then be tested/fed to both class I and class II enzymes and the products isolated and characterized.
A broad spectrum of GGPP unnatural substrates are initially be prepared, exploring both spatial and electronic considerations. Altered backbones manipulating carbon numbers, insertion of heteroatoms and shifting double bonds are of interest. These substrates will also be functionalized with halogens, oxygen, nitrogen, and sulfur. More than a dozen compounds have been synthesized. The test-learn-design cycle is used to identify subgroups of acceptable substrates for further subtle structural refinement will be applied. Substrates are prepared according to Scheme 1, shown below.
Recognizing that Scheme 1 generally shows activation of an allylic center and formation of the pyrophosphate, those of skill in the art should recognize that compounds such as those of the Formulae (III) and (IV) described herein can be accessed via the general methodology described in Scheme 1.
The substrate with a terminal allylic alcohol, substituted as described above, is prepared using methods described by Oberhauser et al. Angew. Chemie Int. Ed. 57, 11802-11806 (2018); Hoshino et al. Chem.—A Eur. J. 18: 13108-13116 (2012); Isaka et al. Biosci. Biotechnol. Biochem. 75: 2213-2222 (2011). The substrate with a terminal allylic alcohol is then converted via a simple two-step process (Davisson et al. J. Org. Chem. 51, 4768-4779 (1986)) to generate the non-natural substrates.
A methyl-derivative of GGPP (‘unGGPP’) was synthesized as described in the previous Example. A comparison of the structures of GGPP and this methyl-derivative of GGPP (‘unGGPP’) is shown below.
DgTPS1 (casbene synthase) was reacted with the unGGPP substrate to yield a novel product with a shifted retention time as detected by gas chromatography (see
Systematic testing against five additional irregular-type diTPS indicated successful bioprocessing of this first substrate by three enzymes. The molecular mass and the fragmentation pattern of the products were consistent with unnatural diterpene-analogs.
A dozen modified unnatural substrates were synthesized and tested for conversion to unnatural products. The results indicated that the enzymes employed had broad substrate tolerance. With only two exceptions, chain and sidechain substituted derivatives were readily accepted and converted by select enzymes of both the class I irregular type and class II labdane-type diTPS. The conversion pattern across all enzymes indicated astounding levels of activity. A total of fifty-six products (possibly with some structural redundancy) were identified in 159 assays (
Class II diTPS forming the decalin core labdanoid-type products catalyze cyclizations initiated by cation formation at carbon C15 of the linear achiral isoprenyl diphosphate, retaining the diphosphate moiety, for example as shown below.
Shown is a typical cyclo-isomerization of GGPP into (4,13)-CLPP and ent-(8,13)-LPP by class II diTPS, where Ar refers to Ajuga reptans, and Pc refers to Pogostemon cablin.
To assess substrate tolerance of class II diTPS, substrates are screened against a panel of twenty-five enzymes. Recombinant diTPS were expressed heterologously in E. coli, purified, and reconstituted in in vitro assays with the substrate to be tested. The products from the enzymatic action on the substrate were analyzed structural elucidation and downstream functionalization.
In particular, pET28b+plasmids containing N-terminally truncated diTPS variants (having the plastidial targeting signal removed to generate pseudomature enzymes) are transformed into E. coli BL-21DE3-C41 OverExpress cells. Cultures are grown at 37° C. and 180 rpm until the optical density at 600 nm reached 0.3 to 0.4. Cultures are cooled to 16° C., and expression is induced at an optical density at 600 nm of approximately 0.6 with 0.2 mM isopropylthiogalactoside. Cells are collected and lysed before purification of the His6-tagged enzymes with Ni-NTA columns.
A typical high-throughput in vitro diTPS assay in lml contained 5 μg substrate, 200 μg purified enzyme (class II plus class I for labdanoid-type diterpenes, or class I for irregular diterpenes), and 10mM buffer with magnesium. Reactions are carried out for 1 hour at 16° C., followed by vortexing with an equal volume of hexane to extract the products into the organic phase, prior to removal for GC/MS analysis.
Active enzyme/substrate combinations are validated by GC/MS analysis of the extract and products compared against references and authentic standards. Structural elucidation of novel products can be by NMR in some cases. The diphosphate intermediate can be converted by lysis to an alcohol for analysis, and the universally acting class I diTPS sclareol synthase from Salvia sclarea can be used for this purpose.
Reactions leading to novel compounds can be scaled up for structural elucidation. The scale-up procedure involved the same composition. However, in coupled assays of pairs of diTPS, the class II enzyme may be pre-incubated with substrate for two hours, before adding the class I diTPS. The diTPS enzymes exhibit excellent stability. Hence, the assays can be extended to overnight reactions to increase product yields, before extraction with hexane.
Thirteen labdane-type diphosphate intermediates (partially redundant with intermediates made from substrate GGPP) were made by the twenty-five plant class II enzymes (see
ent-8,13-copalyl diphosphate (ent-CPP)
normal-(+)-copalyl diphosphate ((+)-CPP)
syn-copalyl diphosphate (syn-CPP)
(+)-8,13-copalyl diphosphate ((8,13)-CPP)
(5S,9S,10S)-labda-7,13Edienyl diphosphate((7,13)-LPP)
ent-(10R)-labda-8,13E-dienyl diphosphate (ent-(8,13)-LPP)
normal-H-labda-13-en-8-ol diphosphate ((+)-8-LPP)
peregrinol (labda-13-en-9-ol diphosphate (PGPP)
(−)-kolavenyl diphosphate (KPP)
(5R,8S,9S,10S)-labda-13-en-8-ol diphosphate (ent-8-LPP)
ent-neo-cis-transclerodienyl diphosphate (CT-CLPP)
(5R,8R,9S,10R)-neo-cleroda-4(18),13E-dienyl diphosphate ((4,13)-CLPP)
(+)-labden-9-ol diphosphate ((+)-9-LPP).
Approximately 100 substrate analogs will be generated. Based on preliminary results (
Class I diTPS use a different chemical strategy for the initial carbocation formation. The diTPS initiate the cascade of cyclization into irregular, macrocyclic or polycyclic compounds by lysis of the isoprenoid diphosphate to yield an allylic cation at the opposite end of the substrate, carbon Ci and inorganic pyrophosphate, for example, as shown below.
Analogously to class II diTPS, the resulting carbocation intermediate further undergoes cyclo-isomerizations including hydride shifts, alkyl migrations and double bond rearrangements before termination of the reaction by proton abstraction or addition of a water molecule. In contrast to the paired modules of class II and I diTPS involved in formation of the labdanoid-type chemistry, irregular diterpenes are formed by the class I diTPS directly (Mau et al. Proc. Natl. Acad. Sci. 91: 8497 LP-8501 (1994)).
To explore unnatural substrate tolerance of the irregular diterpene formation, the inventors are screening all substrates produced in the library against a panel of six plant diTPS, including four macrocyclase-type and two polycyclic—type enzymes, followed by analysis of the products.
The products include the entry-step into the formation of jolkinol C, casbene and the closely related neo-cembrene, next to the structurally more complex taxadiene and hydroxyvulgarisane.
The general function of class I enzymes of labdane-type diterpene metabolism is shared with those yielding irregular polycyclic diterpenes, i.e., generation of the initial carbocation at carbon C1 by metal-dependent ionization.
Instead of accepting the acyclic GGPP, class I enzymes can use structurally diverse decalin-core diphosphate intermediates generated by class II enzymes. At this stage, additional cyclizations, double-bond-, hydride and alkyl shifts can occur, followed by either proton abstraction or quenching of the final carbocation through a water molecule. A panel of eight (seven plant and one microbial) class I labdane-type diTPS was selected for their demonstrated substrate promiscuity (Table 2).
All enzymes in Table 2 were functionally expressed. Microbial sequences were expressed as synthetic variants, expression optimized for E. coli. See also
One example of an enzyme that can accept multiple unnatural substrates is CfTps2, which the inventors have demonstrated can provide the first step in synthesis of the cardiac stimulant and cognition enhancer forskolin. CfTps2 derived from Coleus forskohiii (also referred to as Plectranthus barbatus), an is shown below as SEQ ID NO:69.
The CfTps2 enzyme can also serve as the first step in production of sclareol, manoyl oxide and structurally related compounds which are industrial precursors for ambroxoid fragrance substances.
Similarly, the neo-cleroda-4(18),13E-dienyl diphosphate synthase, which affords entry into a class of insect-antifeedants ArTPS2 is of particular interest for applications in agricultural biotechnology. Neo-clerodane diterpenoids, particularly those with an epoxide moiety at the 4(18) position, such as clerodin, the ajugarins, and the jodrellins have garnered significant attention for their ability to deter insect herbivores. The 4(18) desaturated product of ArTPS2 could be used in biosynthetic or semisynthetic routes to these potent insect antifeedants (BRH: compound 38, below).
The ability to modify, in a targeted manner, these biological active or industrially significant natural products would facilitate the design, testing, and production of novel materials and biologically active agents.
Genetic information was used to reconstruct the pathways to the pharmacologically active cyclic AMP booster forskolin, and jolkinol C (
For example, the inventors have described a CYP726A27 from Euphorbia lathyris, which has the following sequence (SEQ ID NO:70).
The inventors have also described a CYP71D445 from Euphorbia lathyris, which has the following sequence (SEQ ID NO:71).
As illustrated, GGPP is cyclized to the irregular diterpene scaffold Casbene, which is subsequently oxidized and further re-arranged by P450 enzymes and an ADH1. All the functionalization enzymes involved are inherently promiscuous.
The inventors have earlier established the metabolic pathway for oxidative functionalization of casbene to jolkinol C within Euphorbia (
Yeast lines expressing the corresponding characterized functionalization pathways only, i.e., P450s, ACTs and ADHs, can be supplemented with natural untested, and unnatural diterpenes synthetic analogs. Products and intermediates can be purified through the procedures described herein. The structurally elucidated products so generated can include rationally designed derivatives that are not accessible through formal synthesis. Analogs of forskolin are of high interest for their specificity to interact with the specific subgroups of adenylate cyclase, while jolkinol C analogs, not being an immediate pharmaceutical candidate, based on current knowledge, can serve as lead compounds for further chemical diversification.
The inventors have shown highly efficient conversion of labdane-type, synthetic diterpenes, by yeast cell lines expressing P450 enzymes (Hamberger et al. Plant Physiol. 157: 1677-1695 (2011)). See
Yeast cell lines are generated in the industrial strain CEN.PK (CEN.PK2-1C, MATa; his3D1; leu2-3_112; ura3-52; trpl-289; MAL2-8c, SUC2; Entian et al. Methods in Microbiology 36: 629-666 (2007)) that exhibited several advantages, including improved transformability and high tolerance for functionalized terpenoids. Also, the EasyClone 2.0 set of integrative vectors can be used as appropriate for over-expression of heterologous genes in industrial yeast strains. The vectors allow for selection in auxotrophic yeast strains (four different selection markers) and can carry two genes each, which allows for generation of multigene pathways. As the compounds are supplemented to the cultures, this project will not require engineering of the diterpene scaffold biosynthesis, significantly simplifying the generation of yeast strains. P450s, the corresponding cytochrome P450 reductase and enzymes encoding downstream functionalization steps can be stably, chromosomally integrated and driven by various promoters, including constitutive promoters. Isolation of products and analysis can be adapted to the physicochemical properties of the molecules. LC/MS can be used for analysis to offset problems with increasing oxygenation and the increased polarity of products.
Forskolin derivatives are tested for their activity at a representative of each of the three families of membrane adenylyl cyclase (AC1, AC2, and AC5; Dessauer et al. Pharmacol. Rev. 69: 93 LP-139 (2017)). Activation of AC1 could be a potential cognition enhancing target while inhibition may be beneficial in Fragile X syndrome—a genetic autism syndrome. Counter-screens can be done to assess selectivity against AC2 and AC5. Activation of AC5 would be expected to mediate cardiovascular side effects and inhibition may be beneficial. Forskolin itself activates all subtypes of AC so identifying novel derivatives that show selective activation of AC1 without stimulating AC2 or AC5 would be of significant interest. A full exploration of AC drug discovery is beyond the scope of this technology development grant application, but this section will provide initial proof-of-concept results to show potential value of our synthetic biology compound library approach in rationally designing specificity into a known terpenoid AC modulator, forskolin.
AC activity can be tested, as described by Feng et al. Neurology 89: 762 LP-770 (2017) with enhancements made possible by a novel ACA3/6 HEK cell line (Doyle et al. Biochem. Pharmacol. 163: 169-177 (2019)). The inventors can perform subtype-enriched cell-based assays using HEK293 cells transfected with AC1, AC2, and AC5. Cells with vector control plasmid or with plasmids for AC1, 2, or 5 can be stimulated with various concentrations of forskolin analogs (100 nM-30 μM) in the presence of the general PDE inhibitor IBMX. cAMP production can be assessed using the LANCE Ultra cAMP kit (Perkin Elmer; Waltham, Mass.) which is based on a TR-FRET detection method as described by Feng et al. (Neurology 89: 762 LP-770 (2017), see supplement). ACD73/6 HEK-293 cells transfected as indicated above are dissociated from dishes using Versene on the day of experiment. Two thousand cells cells/well in 5 μlin white 384-well microplate (Perkin Elmer) are incubated with various concentrations of forskolin or analogs for 30 min at room temperature. DMSO (0.1%) will be included in all samples for control and forskolin analogs. A cAMP standard curve was generated in triplicate according to the manual. Finally, europium (Eu)-cAMP tracer (54) and ULight™-anti-cAMP (54) were added to each well and incubated for lh at room temperature. Plates will be read on a TR-FRET microplate reader (Synergy NEO; Biotek, Winooski, Vt.) in the MSU Assay Development and Drug Repurposing Core.
Data analysis for forskolin-analog concentration-response curves can include background subtraction of activity in mock-transfected cells to estimate AC1, 2, or 5 specific activity. The resulting curves will be analyzed by non-linear least squares regression analysis to a 4-parameter logistic equation (Rmin, Rmax, —logEC50 e.g. pEC50, and nH) using GraphPad Prism, as described by Feng et al. (Neurology 89:
762 LP-770 (2017). Where curves are well-defined, the pEC50 values for AC1, AC2, and AC5 as well as Rmax values are compared. Where curves may not provide a clear pEC50 value, major differences in Rmax can be noted. Significant selectivity can be defined as a 5-fold or greater differential potency (based on pEC50 values) or 5-fold or greater Rmax value for the chosen AC subtype. In addition to testing for AC activation, the inventors can also test for AC inhibition. Cells will be activated by a forskolin concentration that produces approximately 30% activation (ca. 1 μM) in the presence of increasing concentrations of the forskolin analogs. Any identified selective activators or any derivatives that significantly inhibit AC subtype activity can be tagged for future follow-up studies in receptor-regulated AC activity in HEK or native cells and in WT and AC-subtype KO animals (beyond the scope of the present application).
The catalytic capacities can be determined through gas chromatography and LC-MS analysis of products, i.e., substrate tolerance of entire assembled pathways, which will provide unique mechanistic insights (flux through the pathway, intermediates will indicate the order of conversion, potential steric/electronic hindrance). Hence, novel bioactive labdane and non-labdane type diterpenes can be identified. Structural elucidation of the products of biological interest can be performed using the procedures detailed herein. Analysis of their biological activity against a representative of adenylyl cyclases, either activation, or inhibition is expected to provide valuable data for structural refinement and is of pharmacological relevance.
Ethyl (2E,6E,10E)-2,3,7,11,15-pentamethylhexadeca-2,6,10,14-tetraenoate and ethyl (2Z,6E,10E)-2,3,7,11,15-pentamethylhexadeca-2,6,10,14-tetraenoate. A 25.0 mL 14/20 round bottom flask was charged with sodium hydride (0.344 g, 8.60 mmol), tetrahydrofuran (4.00 mL) was, under an argon atmosphere at 0° C., was treated with triethyl-2-phosphonopropionate (2.05 g, 8.60 mmol) dissolved in tetrahydrofuran (1.00 mL). Once gas evolution ceased, farnesyl acetone (2.25 g, 8.60 mmol) was added, dissolved in tetrahydrofuran (1.00 mL), and the mixture heated to 45° C. for 24 hours. The mixture was cooled to 0° C., quenched with water, and partitioned into ethyl acetate. The organic layer was then washed with brine, dried over sodium sulfate, filtered, and concentrated to dryness. The crude product was dissolved in ethanol (20.0 mL) and cooled to 0° C. Sodium borohydride, to reduce any remaining ketone to ease purification, was added (0.312 g, 8.30 mmol) and the mixture was stirred for 1 hour at room temperature, cooled to 0° C. and quenched with 1.00 N hydrochloric acid. The reaction mixture was concentrated in vacuo and partitioned between ethyl acetate and water. The organic layer was washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The product was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield a mixture of ethyl (2E,6E,10E)-2,3,7,11,15-pentamethylhexadeca-2,6,10,14-tetraenoate and ethyl (2Z,6E,10E)-2,3,7,11,15-pentamethylhexadeca-2,6,10,14-tetraenoate (1.50 g, 50%). 1H NMR (500 MHz, CDCl3) δ 5.18-5.04 (m, 3H), 4.22-4.13 (m, 2H), 2.35 (dd, J=9.6, 6.4 Hz, 1H), 2.20-2.02 (m, 9H), 2.02-1.94 (m, 5H), 1.89-1.82 (m, 3H), 1.78 (d, J=3.3 Hz, 1H), 1.68 (s, 5H), 1.60 (d, J=6.5 Hz, 7H), 1.29 (td, J=7.2, 4.0 Hz, 3H).
(2E,6E,10E)-2,3,7,11,15-pentamethylhexadeca-2,6,10,14-tetraen-1-ol and (2Z,6E,10E)-2,3,7,11,15-pentamethylhexadeca-2,6,10,14-tetraen-1-ol. A 50.0 mL 24/40 round bottom flask was charged with a mixture of ethyl (2E,6E,10E)-2,3,7,11,15-pentamethylhexadeca-2,6,10,14-tetraenoate and ethyl (2Z,6E,10E)-2,3 ,7,11,15 -pentamethylhexadeca-2,6,10,14-tetraenoate (1.10 g, 3.17 mmol), dichloromethane (15.0 mL) and on cooling to 0° C. (argon atmosphere) was treated with a 1.00 M solution of diisobutylaluminum hydride (12.7 mL, 12.7 mmol) in heptanes. The reaction was stirred for 24 hours, the mixture allowed to warm to room temperature then quenched with ethanol (2.00 mL). A solution of sodium potassium tartrate was added (4.50 g, 15.9 mmol in 20.0 mL water) and the biphasic mixture stirred vigorously for 24 hours. The product was then extracted with dichloromethane, the organic layers combined, dried over sodium sulfate, filtered, and concentrated in vacuo to an oil used without further purification (0.722 g, 75%). 1H NMR (500 MHz, CDCl3) δ 5.18-5.06 (m, 3H), 4.15-4.05 (m, 2H), 2.20-1.91 (m, 12H), 1.76 (ddd, J=11.4, 3.0, 1.5 Hz, 4H), 1.71-1.66 (m, 6H), 1.64-1.58 (m, 8H). HRMS ESI (+) calc'd for [M+Na]=327.2664, found=327.2662.
{[(2E,6E,10E)-2,3,7,11,15-pentamethylhexadeca-2,6,10,14-tetraen-1-yl phosphonato]oxy}phosphonate and {[(2Z,6E,10E)-2,3,7,11,15-pentamethylhexadeca-2,6,10,14-tetraen-1-yl phosphonato]oxy}phosphonate. A 100 mL 24/40 round bottom flask was charged with a mixture of (2E,6E,10E)-2,3,7,11,15-pentamethylhexadeca-2,6,10,14-tetraen-1-ol and (2Z,6E,10E)-2,3 ,7,11,15 -pentamethylhexadeca-2,6,10,14-tetraen-1-ol (0.300 g, 1.00 mmol), diethyl ether (5.00 mL) and, under an argon atmosphere, at 0° C. phosphorus tribromide (0.0500 mL, 0.500 mmol) added as a solution in diethyl ether (1.00 mL). After 15 minutes the mixture was diluted with hexanes, washed with brine, sodium bicarbonate and brine, dried over sodium sulfate, filtered, and concentrated in vacuo to dryness as an oil. The residue was redissolved in acetonitrile (5.00 mL), under an argon atmosphere, and treated with tetrabutylammonium pyrophosphate (2.10 g, 2.30 mmol). After 2 hours the reaction mixture was concentrated in vacuo to a viscous liquid and purified on a DOWEX50 column prepared by first stirring the resin (8.70 g) in concentrated ammonium hydroxide (30.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL), suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate mixture) and poured into a column. The excess 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude product applied to the column (dissolved in 3.00 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.550 g, 100%). 31P NMR (202 MHz, Deuterium Oxide) δ −8.57, −10.48 (d, J=20.2 Hz). HRMS ESI [M—H] calcd=463.2020, observed=463.2038.
Ethyl (2Z,6E,10E)-2-fluoro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2E,6E,10E)-2-fluoro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate. A 50.0 mL 14/20 round bottom flask was charged with sodium hydride (0.705 g, 21.0 mmol), tetrahydrofuran (20.0 mL) and at 0° C. (argon atmosphere) was added triethyl-2-fluoro-phosphonoacetate (4.84 g, 20.0 mmol) dissolved in tetrahydrofuran (5.00 mL) via syringe. Once gas evolution ceased, farnesyl acetone (2.62 g, 10 0 mmol) was added as a solution in tetrahydrofuran (1.00 mL). The mixture was heated to 45° C. for 22 hours, then concentrated and partitioned between ethyl acetate and 1.00 N hydrochloric acid. The organic layer was washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield the pure product as a mixture of cis and trans isomers ethyl (2Z,6E,10E)-2-fluoro-3,7,11,15 -tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2E,6E,10E)-2-fluoro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate (3.43 g, 98%). 1H NMR (500 MHz, CDCl3) δ 5.18-5.04 (m, 3H), 4.38-4.21 (m, 3H), 4.11 (p, J=7.2 Hz, 1H), 2.58-2.48 (m, 1H), 2.25 (tt, J=8.8, 4.6 Hz, 1H), 2.16 (dq, J=14.1, 7.0 Hz, 2H), 2.11-2.00 (m, 7H), 1.97 (q, J=7.9 Hz, 3H), 1.86 (d, J=4.3 Hz, 2H), 1.68 (d, J=3.7 Hz, 5H), 1.60 (t, J=4.6 Hz, 7H). 19F NMR (470 MHz, CDCl3) δ −126.96 (dd, J=14.3, 4.8 Hz), −128.66-−128.97 (m).
(2Z,6E,10E)-2-fluoro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-fluoro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol. A 50.0 mL 24/40 round bottom flask was charged with a mixture of ethyl (2Z,6E,10E)-2-fluoro-3,7,11,15 -tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2E,6E,10E)-2-fluoro-3,7,11,15 -tetramethylhexadeca-2,6,10,14-tetraenoate (2.31 g, 6.50 mmol), dichloromethane (20.0 mL) and under an argon atmosphere at 0° C. was added diisobutylaluminum hydride (27.0 mL, 27.0 mmol, 1.00 M in heptanes). The reaction was stirred for 18 hours, warming to room temperature, then quenched with ethanol (5.00 mL) and a solution of sodium potassium tartrate was added (7.00 g, 24.8 mmol in 50.0 mL water). The biphasic mixture was stirred vigorously for 24 hours. The mixture was partitioned in a separatory funnel and the aqueous layer washed with dichloromethane. The organic layers were combined, dried over sodium sulfate, filtered, and concentrated in vacuo to an oil. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield the products (2Z,6E,10E)-2-fluoro-3,7,11,15 -tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-fluoro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol as a mixture of cis and trans isomers (0.859 g, 43%). 1H NMR (500 MHz, CDCl3) δ 5.11 (dt, J=14.5, 7.5 Hz, 3H), 4.22 (dd, J=22.4, 16.6 Hz, 2H), 4.11 (p, J=7.2 Hz, 1H), 2.05 (tdd, J=33.1, 30.9, 10.8, 4.5 Hz, 12H), 1.69 (q, J=3.6, 3.1 Hz, 7H), 1.60 (t, J=3.2 Hz, 8H). 19F NMR (470 MHz, CDCl3) δ −119.15 -−120.01 (m), −121.10-−121.57 (m). HRMS ESI (+) calc'd for [M+Na]=331.2412, found=331.2442.
{[(2Z,6E,10E)-2-fluoro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-yl phosphonato]oxy}phosphonate and {[(2E,6E,10E)-2-fluoro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with a mixture of (2Z,6E,10E)-2-fluoro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-fluoro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol (0.200 g, 0.640 mmol), diethyl ether (5.00 mL) and at 0° C., under an argon atmosphere, was added phosphorus tribromide (0.270 g, 1.00 mmol) dissolved in diethyl ether (1.00 mL). After 15 minutes, the reaction was partitioned between hexanes and brine. The organic layer was washed with sodium bicarbonate, brine, dried over sodium sulfate, filtered, and concentrated in vacuo to an oil. This crude mixture of isomers was dissolved in acetonitrile (2.00 mL), under an argon atmosphere, and treated with tetrabutylammonium pyrophosphate (0.904 g, 1.00 mmol). The reaction mixture was stirred for 2 hours, concentrated in vacuo to a viscous liquid and purified over DOWEX50 (9.40 g) resin. The resin was prepared by first stirring the DOWEX50 in concentrated ammonium hydroxide (30.0 mL) for 20 minutes. The resin was then filtered and washed four times with water (100 mL), then suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude product material applied to the top of the column (dissolved in 3.00 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.250 g, 84%). 31P NMR (202 MHz, Deuterium Oxide) δ −9.34, −11.34. 19F NMR (470 MHz, D2O) δ −117.52 (d, J=133.4 Hz), −118.74 (d, J=144.3 Hz). HRMS ESI [M−H] calcd=467.1769, observed=467.1786.
Ethyl (2E,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2Z,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate. A 25.0 mL 14/20 round bottom flask was charged with sodium hydride (0.839 g, 34.9 mmol), tetrahydrofuran (20.0 mL) was, under argon atmosphere at 0° C., charged with triethyl phosphonobutyrate (4.89 g, 19.4 mmol) dissolved in tetrahydrofuran (2.00 mL). Once gas evolution ceased farnesyl acetone (1.05 g, 4.00 mmol) was added as a solution in tetrahydrofuran (2.00 mL). The reaction mixture was heated to 45° C. for 170 hours, cooled to 0° C., quenched with water and partitioned between ethyl acetate and water. The organic layer was washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a mixture of ethyl (2E,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2Z,6E,10E)-2-ethyl-3,7,11,15 -tetramethylhexadeca-2,6,10,14-tetraenoate, in a 1 to 1 mixture, and unreacted farnesyl acetone. The crude mixture was dissolved in ethanol (20.0 mL), cooled to 0° C. and unreacted farnesyl acetone was reduced with sodium borohydride (0.230 g, 6.20 mmol) to ease purification. The reaction mixture was stirred for 1 hour, allowed to warm to room temperature, cooled to 0° C. and quenched with 1.00 N hydrochloric acid. The reaction mixture was concentrated in vacuo, partitioned between ethyl acetate and water, the organic layer was washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The mixture was purified by silica gel chromatography (0-10% ethyl acetate in hexanes) to yield a mixture of cis and trans isomers, ethyl (2E,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2Z,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate (0.770 g, 31%). 1H NMR (500 MHz, CDCl3) δ 5.12 (dt, J=13.8, 6.0 Hz, 3H), 4.24-4.07 (m, 2H), 2.35-2.21 (m, 3H), 2.19-1.88 (m, 12H), 1.78 (s, 1H), 1.68 (s, 5H), 1.60 (d, J=5.0 Hz, 8H), 1.29 (td, J=7.1, 5.4 Hz, 3H), 1.04-0.80 (m, 3H).
(2E,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2Z,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol. A 50.0 mL 24/40 round bottom flask was charged with a mixture ethyl (2E,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2Z,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate (0.720 g, 2.00 mmol), dichloromethane (20.0 mL) and at 0° C., under an argon atmosphere, treated with diisobutylaluminum hydride (10.0 mL, 10.0 mmol, 1.00 M in heptanes). The mixture was stirred for 18 hours, warming to room temperature. The mixture was again cooled to 0° C., quenched with ethanol (2.00 mL), and a solution of sodium potassium tartrate added (7.10 g, 24.8 mmol in 50.0 mL water) and the biphasic mixture vigorously stirred for 24 hours. The reaction mixture was partitioned, and the aqueous layer washed with dichloromethane. The organic layers were combined, dried over sodium sulfate, filtered, and concentrated in vacuo to an oil. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield an oil (mixture of cis and trans isomers, 0.622 g, 98%). 1H NMR (500 MHz, CDCl3) δ 5.12 (dttd, J=12.5, 5.5, 2.8, 1.4 Hz, 3H), 4.17-4.06 (m, 2H), 2.22-2.12 (m, 3H), 2.08 (tq, J=10.7, 6.2, 5.1 Hz, 8H), 2.02-1.94 (m, 3H), 1.77 (s, 1H), 1.73-1.67 (m, 6H), 1.65-1.57 (m, 8H), 1.01 (qd, J=7.9, 5.5 Hz, 3H), 0.94-0.80 (m, 2H). HRMS ESI (+) calc'd for [M+Na]=341.2820, found=341.2816.
{[(2E,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-yl phosphonato]oxy}phosphonate and {[(2Z,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with a mixture of (2E,6E,10E)-2-ethyl-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2Z,6E,10E)-2-ethyl-3,7,11,15 -tetramethylhexadeca-2,6,10,14-tetraen-1-ol (0.311 g, 1.00 mmol) and anhydrous diethyl ether (5.00 mL). The reaction vessel was sealed, flushed with argon, cooled to 0° C. and phosphorus tribromide (0.405 g, 1.50 mmol) was added dissolved in diethyl ether (1.00 mL). After 15 minutes, the reaction was partitioned between hexanes and brine. The organic layer was then washed with sodium bicarbonate, brine, dried over sodium sulfate, and concentrated in vacuo to dryness as an oil. To this material was added acetonitrile (2.00 mL) and tetrabutylammonium pyrophosphate (0.585 g, 0.645 mmol). The reaction vessel was sealed and stirred, under an argon atmosphere, for 2 hours, then concentrated to a viscous liquid and purified over DOWEX50 resin column. The column was prepared by stirring DOWEX50 resin (8.50 g) in concentrated ammonium hydroxide (30.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate) and poured into a column The excess 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.00 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.230 g, 48%). 31P NMR (202 MHz, Methanol-d4) δ −5.96, −9.82 (d, J=19.2 Hz). HRMS ESI [M−H] calcd.=477.2177, observed=477.2190.
{[(5E,9E)-6,10,14-trimethyl-2-oxopentadeca-5,9,13-trien-1-yl phosphonato]oxy} phosphonate. Using a reported procedure (Hu, T.; Corey, E. J.; Org. Lett., 2002, 4, 2441) a 25.0 mL 14/20 round bottom flask was charged with farnesyl acetone (0.524 g, 2.00 mmol), dichloromethane (32.0 mL), and cooled to 0° C. (argon atmosphere). Diisopropylethylamine (1.55 g, 12.0 mmol) was added, followed by trimethylsilyl triflate (1.77 g, 6.00 mmol) and the mixture stirred at 0° C. for 1.5 hours and then quenched by the addition of sodium bicarbonate. The mixture was extracted with hexanes, the organic layers combined, dried over sodium sulfate, filtered, and concentrated to yield an oil (0.720 g). The crude material was dissolved in tetrahydrofuran (40.0 mL) and solid sodium bicarbonate (0.189 g, 2.25 mmol) was added. The mixture was cooled to −78° C. and, under an argon atmosphere, n-bromosuccinimide (0.371 g, 2.10 mmol) added. The reaction mixture was stirred for 2 hours at −78° C., warmed to room temperature, filtered, and concentrated to yield the crude as a 1:4 mixture of starting material and bromide product (0.572 g, 55%). The crude product was dissolved in acetonitrile (3.00 mL) and tetrabutylammonium pyrophosphate (1.23 g, 1.30 mmol) added. The reaction was stirred at room temperature, under an argon atmosphere for 2 hours, concentrated and purified over DOWEX50 resin according to the following method. DOWEX50 resin (11.8 g) was stirred in concentrated ammonium hydroxide (40.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 millimolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propanol: 25.0 millimolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.00 mL of the 1:49 2-propanol: 25.0 millimolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL of the 1:49 2-propanol: 25.0 millimolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.692 g, 68%). 31P NMR (202 MHz, Deuterium Oxide) δ −5.91, −10.60. HRMS ESI [M−H] calcd=437.1500, observed=437.1511.
2-({ [(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}methyl)prop en-1-ol. A 25.0 mL 14/20 round bottom flask was charged with trans, trans-farnesol (0.889 g, 4.00 mmol), diethyl ether (8.00 mL) and at 0° C. was, under an argon atmosphere, added phosphorus tribromide (1.35 g, 5.00 mmol) dissolved in diethyl ether (1.00 mL). After 1 hour the reaction mixture was diluted with hexanes, washed with brine, sodium bicarbonate, and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to yield trans, trans-farnesyl bromide. A separate 25.0 mL 14/20 round bottom flask was charged with sodium hydride (0.336 g, 10.0 mmol), tetrahydrofuran (8.00 mL) and at to 0° C., under an argon atmosphere, 2-methylidenepropane-1,3-diol (0.704 g, 8.00 mmol) was added in a dropwise fashion. Once gas evolution had ceased, the trans, trans-farnesyl bromide was added (dissolved in 3.00 mL tetrahydrofuran). The reaction was heated to 45° C. for 19 hours, quenched with saturated aqueous ammonium chloride (10.0 mL) and partitioned with ethyl acetate. The crude material was purified by silica gel chromatography (10-100% ethyl acetate in hexanes) to yield the pure product as an oil (0.900 g, 77%). 1H NMR (500 MHz, CDCl3) δ 5.82 (dddd, J=12.6, 7.7, 4.6, 1.4 Hz, 1H), 5.72 (dtd, J=11.1, 6.1, 1.3 Hz, 1H), 5.35 (ddt, J=6.9, 5.5, 1.3 Hz, 1H), 5.14-5.05 (m, 2H), 4.20 (d, J=6.3 Hz, 2H), 4.06-4.03 (m, 2H), 4.01 (d, J=6.9 Hz, 2H), 2.10 (dd, J=14.5, 6.9 Hz, 3H), 2.07-2.01 (m, 5H), 1.97 (dd, J=9.1, 6.2 Hz, 3H), 1.67 (s, 6H), 1.59 (s, 6H). HRMS ESI (+) calc'd for [M+Na]=315.2300, found=315.2314.
{[2-({[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}methyl)prop-2-en-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with 2-({[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}methyl)prop-2-en-1-ol (0.200 g, 0.680 mmol), ether (3.00 mL) and treated, under an argon atmosphere at 0° C., with phosphorus tribromide (0.270, 1.00 mmol) dissolved in diethyl ether (1.00 mL). The reaction mixture was stirred for 30 minutes at 0° C. The organic layer was dried over sodium sulfate, filtered, and concentrated to yield crude (6E,10E)-12-{[2-(bromomethyl)prop-2-en-1-yl]oxy}-2,6,10-trimethyldodeca-2,6,10-triene (0.182 g, 72%). The crude material was dissolved in acetonitrile (2.00 mL), tetrabutylammonium pyrophosphate (0.634 g, 0.7 mmol) was added, the reaction mixture was stirred under argon for 3 hours, at which time it was concentrated and purified over DOWEX50 resin according to the following method. DOWEX50 resin (11.8 g) was stirred in concentrated ammonium hydroxide (40.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.0 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.259 g, 90%). 31P NMR (202 MHz, Deuterium Oxide) δ −5.98 (t, J=21.2 Hz), −9.92 (d, J=20.2 Hz). HRMS ESI [M−H] calc'd=451.1656, observed=451.1666.
(2E)-4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-en-1-ol. A 25.0 mL 14/20 round bottom flask was charged with trans, trans-farnesol (0.222 g, 1.00 mmol), diethyl ether (5.00 mL) and at 0° C., under an argon atmosphere, phosphorus tribromide (0.475 mL, 5.00 mmol) dissolved in diethyl ether (1.00 mL) was added. The mixture was stirred for 30 minutes, diluted with hexanes, washed with brine, sodium bicarbonate, and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to yield trans, trans-farnesyl bromide. A separate 25.0 mL 14/20 round bottom flask was charged with sodium hydride (0.134 g, 4.00 mmol), tetrahydrofuran (6.00 mL) and, under an argon atmosphere at 0° C., but-2-ene-1,4-diol (purchased commercially) was added (0.178 g, 2.00 mmol) in a dropwise fashion. Once gas evolution had ceased, the trans, trans-farnesyl bromide previously prepared was added as a solution in tetrahydrofuran (3.00 mL). The reaction was heated to 45° C. for 19 hours, quenched with saturated ammonium chloride (10.0 mL) and partitioned with ethyl acetate. The crude material was purified by silica gel chromatography (10-100% ethyl acetate in hexanes) to yield the pure product as a clear oil (0.252 g, 86%). 1H NMR (500 MHz, CDCl3) δ 5.89-5.58 (m, 3H), 5.38-5.30 (m, 1H), 5.13-5.04 (m, 2H), 4.70-4.62 (m, 2H), 4.25 (dd, J=6.8, 1.4 Hz, 1H), 4.20 (d, J=6.4 Hz, 2H), 4.04 (d, J=6.2 Hz, 2H), 4.00 (d, J=7.0 Hz, 2H), 2.17-1.90 (m, 8H), 1.67 (s, 6H), 1.59 (s, 6H). HRMS ESI (+) calc'd for [M+Na]=315.2300, found=315.2300.
{[(2E)-4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-en-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with (2E)-4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-en-1-ol (0.314 g, 1.10 mmol), diethyl ether (3.00 mL) and at 0° C., under an argon atmosphere, was added phosphorus tribromide (0.324 g, 1.20 mmol). The mixture was stirred for 20 minutes, diluted with hexanes, washed with brine, sodium bicarbonate, and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to yield crude (6E,10E)-12-{[(2E)-4-bromobut-2-en-1-yl]oxy}-2,6,10-trimethyldodeca-2,6,10-triene (0.262 g, 62%). The crude material was dissolved in acetonitrile (2.00 mL), stirred and treated with tetrabutylammonium pyrophosphate (0.604 g, 0.660 mmol). The reaction mixture was stirred, under an argon atmosphere, for 2 hours, at which time it was concentrated in vacuo and purified over DOWEX50 resin column. The column was prepared by stirring DOWEX50 resin (8.50 g) in concentrated ammonium hydroxide (25.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propanol: 25.0 aqueous mmolar ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.00 mL of 1:49 2-propanol: 25 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.196 g, 44%). 31P NMR (202 MHz, Deuterium Oxide) δ −5.70-−6.25 (m), −9.92 (dd, J=66.8, 21.3 Hz). HRMS ESI [M−H] calcd=451.1656, observed=451.1662.
tert-butyl({[2E)-3-methyl-4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-en-1-yl]oxy})diphenylsilane. A 25.0 mL 14/20 round bottom flask was charged with a stir bar, trans, trans-farnesol (0.444 g, 2.00 mmol), diethyl ether (10.0 mL) and phosphorus tribromide (0.812 g, 3.00 mmol dissolved in 1.00 mL diethyl ether) at 0° C. under an argon atmosphere. After 30 minutes the mixture was diluted with hexanes, washed with brine, sodium bicarbonate, and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to yield trans, trans-farnesyl bromide. A separate 25.0 mL 14/20 round bottom flask was charged with sodium hydride (0.087 g, 2.60 mmol), tetrahydrofuran (5.00 mL), and under argon at 0° C. (2E)-4-[(tert-butyldiphenylsilyl)oxy]-2-methylbut-2-en-1-ol (0.749 g, 2.20 mmol, prepared according to the method described in Oberhauser, C.; Harms, V.; Seidel, K.; Schrçder, B.; Ekramzadeh, K.; Beutel, S,; Winkler, S.; Lauterbach, L.; Dickschat, J. S.; and Kirschning, A.; Angew. Chemie. Int. Ed., 2018, 57, 11802.) was added. Once gas evolution ceased, the trans, trans-farnesyl bromide previously prepared was added as a solution dissolved in tetrahydrofuran (2.00 mL). The reaction was heated to 45° C. for 21 hours, quenched with saturated ammonium chloride (10.0 mL) and partitioned with ethyl acetate. The crude material was purified by silica gel chromatography (hexanes) to yield the pure product as an oil (0.390 g, 37%). 1H NMR (500 MHz, CDCl3) δ 7.75-7.67 (m, 4H), 7.47-7.36 (m, 6H), 5.66 (ddt, J=7.5, 4.9, 1.4 Hz, 1H), 5.37 (dddd, J=8.1, 5.5, 2.6, 1.3 Hz, 1H), 5.16-5.07 (m, 2H), 4.28 (dq, J=6.0, 0.9 Hz, 2H), 3.93 (d, J=6.6 Hz, 2H), 3.84 (d, J=1.2 Hz, 2H), 2.17-2.03 (m, 7H), 1.99 (dd, J=9.2, 5.9 Hz, 3H), 1.69 (q, J=1.3 Hz, 3H), 1.67 (d, J=1.4 Hz, 3H), 1.61 (dd, J=2.2, 1.2 Hz, 6H), 1.50 (t, J=1.1 Hz, 3H), 1.06 (d, J=2.8 Hz, 9H).
(2E)-3-methyl-4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-en-1-ol. A 50.0 mL 24/40 round bottom flask was charged with tert-butyl({[(2E)-3-methyl-4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-en-1-yl]oxy})diphenylsilane (1.01 g, 1.90 mmol) and a stir bar. Under an argon atmosphere, tetrabutylammonium fluoride was added (15.0 mL, 15.0 mmol). The reaction mixture was heated to 45° C. for 16 hours, diluted with ethyl acetate, washed with 1.00 N HCl (20.0 mL), brine, and concentrated to an oil. The crude material was purified by silica gel chromatography (0-100% ethyl acetate in hexanes) to yield the product as an oil (0.263 g, 45%,). 1H NMR (500 MHz, CDCl3) δ 5.67 (tq, J=6.8, 1.3 Hz, 1H), 5.37 (tq, J=6.8, 1.3 Hz, 1H), 5.11 (ddddd, J=11.4, 7.0, 5.6, 2.8, 1.4 Hz, 2H), 4.22 (d, J=6.7 Hz, 2H), 3.97 (d, J=6.8 Hz, 2H), 3.87 (d, J=1.3 Hz, 2H), 2.16-2.03 (m, 7H), 1.98 (dd, J=9.1, 6.1 Hz, 2H), 1.72 (d, J=1.4 Hz, 3H), 1.69 (q, J=1.3 Hz, 3H), 1.67 (d, J=1.3 Hz, 3H), 1.61 (s, 6H). HRMS ESI (+) calc'd for [M+Na]=329.2457, found=329.2475.
{[(2E)-3-methyl-4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien yl]oxy}but-2-en-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with (2E)-3-methyl-4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-en-1-ol (0.263 g, 0.850 mmol), diethyl ether (4.00 mL) and at 0° C., under an argon atmosphere, phosphorus tribromide (0.270 g, 1.00 mmol) was added. The mixture stirred for 30 minutes, diluted with hexanes, washed with brine, sodium bicarbonate, and brine. The organic layer was dried over sodium sulfate, filtered and concentrated in vacuo to yield the crude (6E,10E)-12-{[(2E)-4-bromo-2-methylbut-2-en-1-yl]oxy}-2,6,10-trimethyldodeca-2,6,10-triene (0.0720 g). The crude material was then dissolved in acetonitrile (1.00 mL), stirred and tetrabutylammonium pyrophosphate (0.497 g, 0.540 mmol) added and stirred under an argon atmosphere for 3 hours. The mixture was then concentrated in vacuo and purified over DOWEX50 resin column. The resin (6.80 g) was prepared by stirring in concentrated ammonium hydroxide (25.0 mL) for 20 minutes, then filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.00 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.156 g, 40%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.01 (d, J=21.2 Hz), −9.88 (t, J=25.2 Hz). HRMS ESI [M−H] calcd=465.1813, observed=465.1814.
(2E,6E,10E)-12-[(tert-butyldiphenylsilyl)oxy]-2,6,10-trimethyldodeca-2,6,10-trien-1-ol. A 100 mL 24/40 round bottom flask was charged with trans,trans-farnesol (4.50 g, 20.2 mmol), imidazole (2.99 g, 44.4 mmol) and dimethylformamide (25.0 mL). The reaction mixture was stirred, under an argon atmosphere, and tert-butyldiphenylsilyl chloride added (5.70 mL, 22.0 mmol) dropwise. The mixture was stirred for 19 hours at room temperature, then partitioned between 1.00 N HCl (30.0 mL) and ethyl acetate. The organic layer was washed with sodium bicarbonate, twice with brine, dried over sodium sulfate, filtered, and concentrated in vacuo to provide crude tert-butyldiphenyl {[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}silane (8.71 g, 95%).
In a separate 100 mL 24/40 round bottom flask was added selenium(IV) dioxide (0.103 g, 0.94 mmol), salicylic acid (0.259 g, 1.88 mmol) and dichloromethane (40.0 mL). The mixture was stirred at room temperature and tent-butylhydroperoxide added (9.00 mL, 65.8 mmol, 70% solution in water), followed by tert-butyldiphenyl {[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}silane (8.71 g, 18.8 mmol, dissolved in 5.00 mL dichloromethane). The mixture was stirred at room temperature for 50 hours, washed with saturated sodium thiosulfate and concentrated in vacuo. The material was then dissolved in ethanol, cooled to 0° C., and treated with sodium borohydride (0.720 g, 19.0 mmol). After gas evolution ceased the reaction was warmed to room temperature and stirred for 30 minutes. The reaction was quenched with 1.00 N HCl (10.0 mL), partitioned between ethyl acetate and sodium bicarbonate, washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo to yield the crude product as a red oil. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield the product as a clear oil (1.2 g, 13% yield). 1H NMR (500 MHz,CDCl3) δ 7.74-7.66 (m, 4H), 7.46-7.34 (m, 6H), 5.40 (dddt, J=6.3, 5.0, 2.6, 1.3 Hz, 2H), 5.14 (tq, J=6.9, 1.4 Hz, 1H), 4.29-4.19 (m, 2H), 4.02 (d, J=19.9 Hz, 2H), 2.20-1.95 (m, 8H), 1.69 (dd, J=14.6, 1.4 Hz, 3H), 1.62 (s, 3H), 1.45 (d, J=1.2 Hz, 3H), 1.05 (s, 9H).
(2E,6E,10E)-3,7,11-trimethyl-12-[(3-methylbut-2-en-1-yl)oxy]dodeca-2,6,10-trien-1-ol. A 25.0 mL 14/20 round bottom flask was charged with (2E,6E,10E)-12-[(tert-butyldiphenylsilyl) oxy]-2,6,10-trimethyldodeca-2,6,10-trien-1-ol (0.478 g, 1.00 mmol) and tetrahydrofuran (5.00 mL). The mixture was cooled to 0° C. and sodium hydride added (0.170 g, 7.00 mmol) under an argon atmosphere, followed by the addition of prenyl bromide (1.00 g, 6.20 mmol). The mixture was stirred at 40° C. for 22 hours and quenched with saturated ammonium chloride, partitioned into ethyl acetate and the organic layer washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by silica gel chromatography (100% hexanes) to yield the product as an oil. This material was dissolved in tetrabutylammonium fluoride (10.0 mL, 10.0 mmol) and heated to 40° C. for 19 hours under argon. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield the product (0.171 g, 58%). 1H NMR (500 MHz, CDCl3) δ 5.43-5.31 (m, 3H), 5.10 (tq, J=6.9, 1.4 Hz, 1H), 4.12 (dd, J=13.9, 7.1 Hz, 2H), 3.90-3.84 (m, 2H), 3.82 (d, J=1.1 Hz, 2H), 2.17-1.97 (m, 8H), 1.73 (d, J=1.4 Hz, 3H), 1.66 (d, J=1.4 Hz, 3H), 1.65 (d, J=1.4 Hz, 3H), 1.64 (d, J=1.4 Hz, 3H), 1.59 (d, J=1.4 Hz, 3H).
{[(2E,6E,10E)-3,7,11-trimethyl-12-[(3-methylbut-2-en-1-yl)oxy]dodeca-2,6,10-trien-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with (2E,6E,10E)-3,7,11-trimethyl-12-[(3-methylbut-2-en-1-yl)oxy]dodeca-2,6,10-trien-1-ol (0.171 g, 0.580 mmol), diethyl ether (4.00 mL) and at 0° C. under an argon atmosphere, treated phosphorus tribromide (0.094 mL, 1.00 mmol). The reaction mixture was stirred for 30 minutes, diluted with hexanes, the organic layer was then washed with brine, sodium bicarbonate, and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to yield crude (2E,6E,10E)-12-bromo-2,6,10-trimethyl-1-[(3 -methylbut-2-en-1-yl)oxy]dodeca-2,6,10-triene (0.122 g). The crude material was then dissolved in acetonitrile (1.00 mL), stirred and treated with tetrabutylammonium pyrophosphate (0.500 g, 0.540 mmol). The reaction mixture was stirred, under an argon atmosphere, for 2 hours, then concentrated in vacuo and purified over DOWEX50 resin (6.89 g) column prepared by stirring in concentrated ammonium hydroxide (30.0 mL) for 20 minutes, then filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propanol: 25 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.00 mL of the 1:49 2-propanol: 25 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL of the 1:49 2-propanol: 25 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.138 g, 60%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.03 (d, J=21.2 Hz), -9.99 (d, J=20.6 Hz). HRMS ESI [M−H] calcd=465.1813, observed=465.1810.
Tert-butyl({[2-({[(5E)-6,10-dimethylundeca-5,9-dien-2-yl]oxy}methyl)prop-2-en-1-yl]oxy})diphenylsilane. A 100 mL 24/40 round bottom flask was charged with geranyl acetone (1.94 g, 10.0 mmol) and ethanol (30.0 mL). The reaction mixture was cooled to 0° C. and sodium borohydride added (0.529 g, 14.0 mmol) and stirred for 1.0 hour, quenched with 1.00 N HCl (10.0 mL) and partitioned with ethyl acetate. The organic layer was filtered through a plug of silica gel (eluted with 100% ethyl acetate) and concentrated to yield crude (5E)-6,10-dimethylundeca-5,9-dien-2-ol (1.80 g, 91%), which was used without further purification.
Using the method of Vita and coworkers (Vita, M. V.; Caramenti. P.; Waser, J. Org. Lett., 2015, 17, 5832.), a separate 250 mL 24/40 round bottom flask was charged prop-2-ene-1,3-diol (8.40 mL, 102 mmol) and tetrahydrofuran (50.0 mL) under an argon atmosphere. The flask was cooled to 0° C. and sodium hydride added (3.69 g, 110 mmol), followed by tent-butyldiphenylsilyl chloride (25.9 mL, 100 mmol). The reaction was stirred for 20 hours, partitioned into ethyl acetate, which was washed with a saturated ammonium chloride solution, concentrated in vacuo and purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield 2-{[(tert-butyldiphenylsilyl)oxy]methyl}prop-2-en-1-ol (8.00 g, 23%). 1H NMR (500 MHz, Chloroform-d) δ 7.71-7.68 (m, 4H), 7.48-7.38 (m, 6H), 5.72 (dtt, J=11.5, 5.7, 1.3 Hz, 1H), 5.65 (dtt, J=11.2, 6.4, 1.4 Hz, 1H), 4.31-4.25 (m, 2H), 4.02 (d, J=6.2 Hz, 2H), 1.06 (s, 9H).
2-{[(tert-butyldiphenylsilyl)oxy]methyl}prop-2-en-1-ol (1.31 g, 4.00 mmol, Heidelbrecht, R. W. Jr.; Gulledge, B.; Martin, S., Org. Lett., 2010, 12, 2492.) was dissolved in dichloromethane (15.0 mL), cooled to 0° C. and triphenylphosphine added (1.25 g, 4.80 mmol), followed by n-bromosuccinimide (0.782 g, 4.80 mmol). The mixture was stirred under an argon atmosphere for 2 hours at 0° C. and treated with hexanes (200 mL). The solid was filtered and the filtrate concentrated to yield {[2-(bromomethyl)prop-2-en-1-yl]oxy}(tert-butyl)diphenylsilane (1.10 g, 71%). The product was used without further purification. 1H NMR (500 MHz, Chloroform-d) δ 7.71-7.67 (m, 4H), 7.46-7.39 (m, 6H), 5.78-5.72 (m, 2H), 4.34-4.32 (m, 2H), 3.87-3.84 (m, 2H), 1.06 (s, 9H).
A 14/20 25.0 mL round bottom flask was charged with crude {[2-(bromomethyl)prop-2-en-1-yl]oxy }(tert-butyl)diphenylsilane (0.960 g, 2.30 mmol), crude (5E)-6,10-dimethylundeca-5,9-dien-2-ol (0.976 g, 5.00 mmol), tetrahydrofuran (5.00 mL), cooled to 0° C., and treated with sodium hydride (0.235 g, 7.00 mmol). After gas evolution was complete, the mixture was heated to 45° C. for 19 hours under an argon atmosphere. The reaction was partitioned between ethyl acetate and ammonium chloride, washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield an oil (0.500 g, 1.00 mmol). 1H NMR (500 MHz, Chloroform-d) δ 7.72-7.67 (m, 4H), 7.48-7.36 (m, 6H), 5.79-5.71 (m, 2H), 5.64-5.55 (m, 1H), 5.10 (ttq, J=7.2, 4.4, 1.3 Hz, 1H), 4.33 (dd, J=3.3, 2.2 Hz, 1H), 4.29-4.25 (m, 1H), 3.97-3.76 (m, 4H), 2.10-1.95 (m, 4H), 1.69 (t, J=1.3 Hz, 3H), 1.61 (t, J=1.7 Hz, 3H), 1.59-1.54 (m, 3H), 1.09-1.03 (m, 9H), 1.00 (s, 3H).
A 25.0 mL 14/20 round bottom flask was charged with tert-butyl({[2-({[(5E)-6,10-dimethylundeca-5,9-dien-2-yl]oxy}methyl)prop-2-en-1-yl]oxy})diphenylsilane (0.500 g, 1.00 mmol) and, under an argon atmosphere, tetrabutylammonium fluoride (5.00 mL, 5.00 mmol) added. The reaction mixture was stirred at 45° C. for 15 hours then partitioned between ethyl acetate and 1.00 N HCl (15.0 mL). The organic layer was washed with brine and purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield 2-({[(5E)-6,10-dimethylundeca-5,9-dien-2-yl]oxy}methyl)prop-2-en-1-ol (0.100 g, 38%). 1H NMR (500 MHz, Chloroform-d) δ 5.83-5.75 (m, 1H), 5.75-5.66 (m, 1H), 5.09 (dddddd, J=12.7, 7.0, 5.7, 4.3, 2.8, 1.4 Hz, 2H), 4.18 (dt, J=6.4, 1.2 Hz, 2H), 4.14-4.06 (m, 1H), 3.97 (dddd, J=12.4, 6.2, 2.3, 1.4 Hz, 1H), 3.44 (hept, J=6.4 Hz, 1H), 2.09-1.94 (m, 7H), 1.68 (dq, J=4.2, 1.3 Hz, 3H), 1.64-1.50 (m, 6H), 1.47-1.36 (m, 1H), 1.15 (dd, J=6.2, 2.3 Hz, 3H).
{[2-({[(5E)-6,10-dimethylundeca-5,9-dien-2-yl]oxy}methyl)prop-2-en-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with 2-({[(5E)-6,10-dimethylundeca-5,9-dien-2-yl]oxy}methyl)prop-2-en-1-ol (0.100 g, 0.380 mmol), diethyl ether (4.00 mL), cooled to 0° C., and phosphorus tribromide was added (0.270 g, 1.00 mmol). He reaction mixture was stirred for 30 minutes at 0° C., diluted with hexanes, washed with brine, sodium bicarbonate, and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to yield the crude (6E)-10-{[2-(bromomethyl)prop-2-en-1-yl]oxy}-2,6-dimethylundeca-2,6-diene (0.0400 g, 32%). The crude material was dissolved in acetonitrile (2.00 mL), stirred, and tetrabutylammonium pyrophosphate (0.604 g, 0.670 mmol) was added. The reaction mixture was stirred under an argon atmosphere for 2 hours, at which time it was concentrated in vacuo and purified over DOWEX50 resin column. The column was prepared by stirring DOWEX50 resin (7.00 g) in concentrated ammonium hydroxide (30.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.00 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.128 g, 82%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.03 (d, J=22.8 Hz), −10.05 (d, J=22.0 Hz). HRMS ESI [M−H] calcd=425.1500, observed=425.1502.
Tert-butyl({[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy})diphenylsilane. A 250 mL 24/40 round bottom flask was charged with trans,trans-geraniol (4.62 g, 30.0 mmol), imidazole (2.72 g, 40.0 mmol) and dimethylformamide (90.0 mL). The reaction mixture was stirred under an argon atmosphere and tert-butyldiphenylsilyl chloride added (8.55 g, 31.0 mmol) in a dropwise fashion. The reaction was stirred for 19 hours at room temperature, portioned between 1.00 N HCl (30.0 mL) and ethyl acetate. The organic layer was washed with a saturated sodium bicarbonate solution, twice with brine, dried over sodium sulfate, filtered, and concentrated in vacuo to a clear oil (8.41 g, 70%). 1H NMR (500 MHz, Chloroform-d) δ 7.74-7.69 (m, 4H), 7.47-7.35 (m, 6H), 5.40 (dddt, J=7.6, 6.2, 3.3, 1.4 Hz, 2H), 4.23 (dq, J=6.3, 0.9 Hz, 2H), 4.00 (d, J=1.3 Hz, 2H), 2.21-2.10 (m, 2H), 2.03 (dd, J=9.1, 6.3 Hz, 2H), 1.68 (d, J=1.3 Hz, 3H), 1.46 (d, J=1.3 Hz, 4H), 1.05 (s, 9H).
(2E,6E)-8-[(tert-butyldiphenylsilyl)oxy]-2,6-dimethylocta-2,6-dien-1-ol. In a 100 mL 24/40 round bottom flask was added selenium(IV) dioxide (0.118 g, 1.07 mmol), salicylic acid (0.295 g, 2.14 mmol) and dichloromethane (40.0 mL). The reaction mixture was stirred at room temperature and tent-butylhydroperoxide was added (10.0 mL, 73.1 mmol, 70% solution in water), followed by tert-butyl({[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy})diphenylsilane (8.71 g, 18.8 mmol dissolved in 5.00 mL dichloromethane). The reaction mixture was stirred at room temperature for 75 hours, washed with a saturated sodium thiosulfate solution and concentrated in vacuo. This material was dissolved in ethanol, cooled to 0° C., and treated with sodium borohydride (0.832 g, 22.0 mmol). After gas evolution ceased, the reaction was warmed to room temperature and stirred for 1 hour, quenched with 1.00 N hydrochloric acid (20.0 mL), partitioned between ethyl acetate and sodium bicarbonate, the organic layer washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo to yield the crude product as an oil. The crude material was purified by silica gel chromatography (0-100% ethyl acetate in hexanes) to yield the product as an oil (1.20 g, 13% yield). 1H NMR (500 MHz, CDCl3) δ 7.74-7.66 (m, 4H), 7.47-7.34 (m, 6H), 5.40 (dddt, J=7.6, 6.3, 3.3, 1.4 Hz, 2H), 4.23 (dq, J=6.3, 0.9 Hz, 2H), 4.00 (d, J=1.1 Hz, 2H), 2.19-2.09 (m, 2H), 2.03 (dd, J=9.1, 6.3 Hz, 2H), 1.68 (d, J=1.4 Hz, 3H), 1.46 (d, J=1.3 Hz, 3H), 1.05 (s, 9H). HRMS ESI (+) calc'd for [M+Na]=329.2457, found=329.2448.
Tert-butyl({[(2E,6E)-8-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}-3,7-dimethylocta-2,6-dien-1-yl]oxy})diphenylsilane. A 25.0 mL 14/20 round bottom flask was charged with (2E,6E)-8-[(tert-butyldiphenylsilyl)oxy]-2,6-dimethylocta-2,6-dien-1-ol (0.752 g, 2.0 mmol) and tetrahydrofuran (5.00 mL). The reaction mixture was cooled to 0° C. and sodium hydride was added (0.134 g, 4.00 mmol). Under an argon atmosphere, geranyl bromide (0.650 g, 3.00 mmol, Brundel, B., J., J., M.; Steen, H.; Heeres, A.; Seerden, J. P. G., WO2013157926) was added and the mixture stirred at 40° C. for 20 hours. The reaction was quenched with ammonium chloride, partitioned with ethyl acetate, washed with brine, dried over sodium sulfate, filtered and the solvent removed in vacuo. The crude material was purified by silica gel chromatography (100% hexanes) to yield the product as an oil (0.470 g, 43%). 1H NMR (500 MHz, CDCl3) δ 7.73-7.67 (m, 4H), 7.46-7.34 (m, 6H), 5.44-5.33 (m, 3H), 5.15-5.02 (m, 1H), 4.23 (d, J=6.0 Hz, 2H), 3.95-3.90 (m, 2H), 3.87-3.80 (m, 2H), 2.16-1.99 (m, 8H), 1.72-1.65 (m, 6H), 1.59 (s, 6H), 1.45 (d, J=1.2 Hz, 3H), 1.05 (s, 9H).
(2E,6E)-8-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}-3,7-dimethylocta-2,6-dien-1-ol. Tert-butyl({[(2E,6E)-8-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}-3,7-dimethylocta-2,6-dien-1-yl]oxy})diphenylsilane was dissolved in tetrahydrofuran (2.00 mL), treated with a 1.00 M tetrabutylammonium fluoride (10.0 mL, 10.0 mmol) solution (in tetrahydrofuran) and heated to 40° C. for 19 hours under an argon atmosphere. The mixture was treated with water then extracted with ethyl acetate. The organic layers were combined, dried with sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield the product (0.100 g, 42% yield). 1H NMR (500 MHz, CDCl3) δ 5.46-5.30 (m, 3H), 5.10 (ddp, J=7.1, 5.8, 1.5 Hz, 1H), 4.15 (d, J=6.9 Hz, 2H), 3.93 (d, J=6.8 Hz, 2H), 3.83 (d, J=1.2 Hz, 2H), 2.24-1.97 (m, 8H), 1.69 (d, J=1.3 Hz, 6H), 1.66 (d, J=1.3 Hz, 5H), 1.62-1.59 (m, 3H). {[(2E,6E)-8-{[(2Z)-3,7-dimethylocta-2,6-dien-1yl]oxy}-3,7-dimethylocta-2,6-dien-1-yl phosphonato]oxy}phosphonate. The alcohol (2E,6E)-8-{[(2Z)-3,7-dimethylocta-2,6-dien-1-yl]oxy}-3,7-dimethylocta-2,6-dien-1-ol (0.100 g, 0.340 mmol) was dissolved in diethyl ether (2.00 mL) and at 0° C., under an argon atmosphere, was added phosphorus tribromide (0.270 mL, 1.00 mmol). The reaction mixture was stirred for 30 minutes, diluted with hexanes, washed with brine, sodium bicarbonate, and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to yield (2E,6E)-8-bromo-1-{[(2Z)-3,7-dimethylocta-2,6-dien-1-yl]oxy}-2,6-dimethylocta-2,6-diene (0.121 g, 96%). The crude material was dissolved in acetonitrile (2.00 mL) and tetrabutylammonium pyrophosphate (0.255 g, 0.280 mmol) added. The reaction mixture was stirred under an argon atmosphere for 2 hours, at which time it was concentrated in vacuo and purified over a DOWEX50 resin column. The column was prepared by treating DOWEX50 resin (7.20 g) with concentrated ammonium hydroxide (30.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.00 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.066 g, 60% yield by mass, 95% yield by 31P NMR integration). 31P NMR (202 MHz, Deuterium Oxide) δ −6.43 (d, J=97.1 Hz), −9.83-−11.41 (m). HRMS ESI [M−H] calcd=465.1813, observed=465.1814.
(2E,6E,10E)-13-(3,3-dimethyloxiran-2-yl)-3,7,11-trimethyltrideca-2,6,10-trien-1-ol and (2Z,6E,10E)-13-(3,3-dimethyloxiran-2-yl)-3,7,11-trimethyltrideca-2,6,10-trien-1-ol. A 50.0 mL 24/40 round bottom flask was charged with geranyl geraniol (1.00 g, 3.50 mmol, Look, G. C., WO2015006614) as a mixture of (2E,6E,10E)-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2Z,6E,10E)-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol), dichloromethane (10.0 mL), triethylamine (0.696 mL, 5.00 mmol), stirred and cooled to 0° C. To the mixture was added acetic anhydride (0.378 mL, 4.00 mmol) and dimethylaminopyridine (0.0240 g, 0.200 mmol). The reaction was stirred for 1 hour at 0° C. and quenched with brine, dried over sodium sulfate, and concentrated to yield the product as a mixture of (2E,6E,10E)-13-(3,3-dimethyloxiran-2-yl)-3,7,11-trimethyltrideca-2,6,10-trien-1-yl acetate and (2Z,6E,10E)-13-(3,3-dimethyloxiran-2-yl)-3,7,11-trimethyltrideca-2,6,10-trien-1-yl acetate (0.980 g, 84%). The oil was dissolved in a mixture of tetrahydrofuran (25.0 mL) and water (10.0 mL), cooled to 0° C., and n-bromosuccinimide (0.623 g, 3.50 mmol). The reaction was stirred at 0° C. for 2 hours, concentrated and extracted with hexanes. The organic layer was washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo to yield the intermediate as an oil (1.21 g). This material was dissolved in methanol (15.0 mL), potassium carbonate was added (0.720 g, 5.20 mmol) and the mixture was stirred for 17 hours. The reaction mixture was partitioned with ethyl acetate, filtered through a plug of silica (100% ethyl acetate) and concentrated to yield the product 3-[(3E,7E,11E)-13-bromo-3,7,11-trimethyltrideca-3,7,11-trien-1-yl]-2,2-dimethyloxirane and 3-[(3E,7E,11Z)-13-bromo-3,7,11-trimethyltrideca-3,7,11-trien-1-yl]-2,2-dimethyloxirane (0.823 g, 96%). 1H NMR (500 MHz, Chloroform-d) δ 5.39-5.31 (m, 1H), 5.10 (dddqd, J=8.4, 6.9, 4.1, 2.7, 1.9, 1.4 Hz, 3H), 4.62-4.54 (m, 2H), 2.16-2.01 (m, 14H), 1.97 (dd, J=9.1, 6.3 Hz, 2H), 1.74-1.66 (m, 8H), 1.63-1.57 (m, 6H). HRMS ESI (+) calc'd for [M+Na]=329.2457, found=329.2455.
{[(2E,6E,10E)-13-(3,3-dimethyloxiran-2-yl)-3,7,11-trimethyltrideca-2,6,10-trien-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with dichloromethane (10.0 mL) and n-chlorosuccinimide (0.267 g, 2.00 mmol). The mixture was stirred under argon, cooled to −30° C., and dimethyl sulfide was added (0.146 mL, 2.00 mmol). The reaction was warmed to 0° C. for 5 minutes, again cooled to −30° C. and (2E,6E,10E)-13-(3,3-dimethyloxiran-2-yl)-3,7,11-trimethyltrideca-2,6,10-trien-1-ol added (0.306 g, 1.00 mmol, dissolved in 1.0 mL dichloromethane). The mixture was stirred for 5 minutes at −30° C. then warmed to 0° C. for 2 hours. The mixture was then washed with brine and concentrated to dryness to yield the crude 3-[(3E,7E,11E)-13-chloro-3,7,11-trimethyltrideca-3,7,11-trien-1-yl]-2,2-dimethyloxirane (0.301 g, 0.920 mmol). This material was dissolved in acetonitrile (2.00 mL), stirred (argon atmosphere), then treated with tetrabutylammonium pyrophosphate (0.525 g, 0.570 mmol). The reaction mixture was stirred for 2 hours, then concentrated in vacuo and purified on a DOWEX50 resin column. The column was prepared by treating the resin (7.20 g) with concentrated ammonium hydroxide (30 mL) for 20 minutes then filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20 mL of 1:49 2-propanol: 25.0 mmolar ammonium bicarbonate) and poured into a column. The excess buffer was drained from the column and the crude product was applied to the column (dissolved in 3.00 mL of the same buffer). The material was eluted with 30 mL buffer and lyophilized to a waxy solid (0.083 g, 18%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.24 (d, J=21.8 Hz), −10.09 (d, J=22.4 Hz). HRMS ESI [M−H] calc'd=465.1813, observed=465.1816.
3-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}benzaldehyde. A 25.0 mL 14/20 round bottom flask was charged with trans,trans-farnesol (0.889 g, 4.00 mmol), diethyl ether, (10.0 mL), and at 0° C. under argon was added phosphorus tribromide (1.35 g, 5.00 mmol). The reaction mixture was stirred for 30 minutes, diluted with hexanes, washed with brine, a saturated sodium bicarbonate solution, and brine. The organic layer was dried over sodium sulfate, filtered and concentrated in vacuo to yield crude trans, trans-farnesyl bromide (0.937 g, 83%). This material was diluted with tetrahydrofuran (10.0 mL) and 3-hydroxybenzaldehyde (0.463 g, 3.80 mmol) was added. The reaction mixture was cooled to 0° C. and sodium hydride added (0.151 g, 4.50 mmol). Once gas evolution ceased, the reaction mixture was heated to 45° C. for 23 hours under an argon atmosphere. The mixture was then partitioned between ethyl acetate and saturated ammonium chloride. The organic layer washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo. The crude material was purified by silica gel chromatography (1:9:0.1 ethyl acetate: hexanes: triethylamine) to yield the product as an oil (0.490 g, 46%). 1H NMR (500 MHz, CDCl3) δ 9.97 (s, 1H), 7.49-7.37 (m, 3H), 7.19 (dt, J=6.7, 2.5 Hz, 1H), 5.50 (tq, J=6.6, 1.3 Hz, 1H), 5.09 (ddddt, J=11.3, 5.7, 4.3, 2.9, 1.4 Hz, 2H), 4.60 (dd, J=6.6, 1.0 Hz, 2H), 2.18-2.02 (m, 6H), 2.01-1.94 (m, 2H), 1.76 (d, J=1.3 Hz, 3H), 1.68 (q, J=1.3 Hz, 3H), 1.60 (dd, J=2.3, 1.3 Hz, 6H).
(3-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}phenyl)methanol. A 50.0 mL 14/20 round bottom flask was charged with 3-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}benzaldehyde (0.470 g 1.50 mmol), ethanol (6.00 mL), cooled to 0° C., and sodium borohydride (0.0750 g, 2.00 mmol). After 10 minutes, the reaction mixture was partitioned between ethyl acetate and ammonium chloride, the organic layer washed with brine, dried over sodium sulfate, filtered, and concentrated to an oil. The crude material was purified by silica gel chromatography (0-50% ethyl acetate in hexanes) to yield the product as an oil (0.251 g, 51%). 1H NMR (500 MHz, CDCl3) δ 7.27 (t, J=7.8 Hz, 1H), 6.98-6.90 (m, 2H), 6.86 (ddd, J=8.2, 2.7, 1.0 Hz, 1H), 5.51 (tq, J=6.6, 1.3 Hz, 1H), 5.17-5.06 (m, 2H), 4.68 (s, 2H), 4.56 (d, J=6.6 Hz, 2H), 2.21-2.03 (m, 6H), 1.98 (dd, J=9.1, 6.2 Hz, 2H), 1.75 (d, J=1.3 Hz, 3H), 1.69 (d, J=1.4 Hz, 3H), 1.62 (d, J=1.4 Hz, 6H). HRMS ESI (+) calc'd for [M+Na]=351.2300, found=351.2315.
{[(3-{[(2E,6E)-3,6,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}phenyl)methyl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with the alcohol from the prior step, (3-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}phenyl)methanol (0.212 g, 0.640 mmol), diethyl ether (3.00 mL), cooled to 0° C., and under argon was added phosphorus tribromide (0.270 g, 1.00 mmol). The reaction was stirred at 0° C. for 1 hour, diluted with hexanes, washed with brine, sodium bicarbonate, and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to yield the crude bromide as an oil (0.135 g). This material was dissolved in acetonitrile (2.00 mL) and tetrabutylammonium pyrophosphate added (0.409 g, 0.450 mmol) and stirred under an argon atmosphere for 2 hours, at which time it was concentrated in vacuo and purified over DOWEX50 resin column. The column was prepared by stirring DOWEX50 resin (7.20 g) in concentrated ammonium hydroxide (30.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propano1:25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propano1:25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.00 mL of the 1:49 2-propano1:25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL 1:49 2-propanol:25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.163 g, 53%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.45 (d, J=21.9 Hz), −10.37 (d, J=22.6 Hz). HRMS ESI [M−H] calc'd=487.1656, observed=487.1653.
(2-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}phenyl)methanol. A 25.0 mL 14/20 round bottom flask was charged with trans, trans-farnesol (0.889 g, 4.00 mmol), diethyl ether, (10.0 mL), and at 0° C., under an argon atmosphere, was added phosphorus tribromide (1.35 g, 5.00 mmol) and the mixture stirred for 1 hour. The mixture was then diluted with hexanes and the organic layer washed with brine, a saturated sodium bicarbonate solution, and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to yield crude trans, trans-farnesyl bromide (0.769 g, 2.70 mmol). This material was diluted with tetrahydrofuran (10.0 mL) and treated with 2-hydroxy-benzyl alcohol (0.369 g, 3.00 mmol). The mixture was cooled to 0° C. and sodium hydride added (0.100 g, 3.00 mmol). After gas evolution ceased the reaction mixture was heated to 45° C. for 19 hours under an argon atmosphere, partitioned between ethyl acetate and a saturated ammonium chloride solution, washed with brine and concentrated in vacuo as an oil. The crude material was purified by silica gel chromatography (1:9:0.1 ethyl acetate: hexanes: triethylamine) to yield the product as an oil (0.258 g, 29%). 1H NMR (500 MHz, CDCl3) δ 7.26 (ddd, J=7.8, 6.5, 2.0 Hz, 2H), 6.97-6.86 (m, 2H), 5.49 (tq, J=6.4, 1.3 Hz, 1H), 5.10 (dtp, J=8.4, 4.3, 1.4 Hz, 2H), 4.69 (s, 2H), 4.60 (d, J=6.5 Hz, 2H), 2.47 (s, 1H), 2.22-2.03 (m, 6H), 1.98 (dd, J=9.1, 6.0 Hz, 2H), 1.74 (d, J=1.3 Hz, 3H), 1.68 (p, J=1.6 Hz, 3H), 1.61 (dd, J=2.9, 1.4 Hz, 6H). HRMS ESI (+) calc'd for [M+Na]=351.2300, found=351.2340.
{[(2-{[(2E,6E)-3,6,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}phenyl)methyl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with (2-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}phenyl)methanol (0.218 g, 0.660 mmol), diethyl ether (3.00 mL), cooled to 0° C., and under argon atmosphere, treated with phosphorus tribromide (0.270 g, 1.00 mmol). The mixture was stirred at 0° C. for 1 hour, diluted with hexanes, washed with brine, aqueous saturated sodium bicarbonate solution and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to yield crude 1-(bromomethyl)-2-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}benzene as an oil (0.132 g). This material was dissolved in acetonitrile (2.00 mL) and tetrabutylammonium pyrophosphate (0.292 g, 0.450 mmol) added. The reaction mixture was stirred under an argon atmosphere for 2 hours, then concentrated in vacuo and purified over a DOWEX50 resin column. The DOWEX50 column was prepared by first stirring the DOWEX50 (7.55 g) in concentrated ammonium hydroxide (30.0 mL) for 20 minutes and then filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propano1:25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propano1:25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.0 mL of the same buffer). The material was eluted with 30.0 mL 1:49 2-propano1:25.0 mmolar aqueous ammonium bicarbonate and lyophilized to a waxy solid (0.075 g, 46%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.22 (d, J=21.9 Hz), −10.05 (d, J=21.9 Hz). HRMS ESI [M−H] calc'd=487.1656, observed=487.1644.
Ethyl (2Z,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2E,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate. A 100 mL 14/20 round bottom flask was charged with ethyl 2-(diethoxyphosphoryl)-2-ethoxyacetate (2.36 g, 8.80 mmol. Prepared according to the method described in Bach, K.; Hesham, R., E.-S.; Jensen, H. M.; Nielsen, H. B.; Thomson, I.; Torssell, K. B. G; Tetrahedron, 1994, 50, 7543), tetrahydrofuran (15.0 mL), cooled to 0° C., and sodium hydride (0.336 g, 10.0 mmol) added under an argon atmosphere. Farnesyl acetone (1.57 g, 6.00 mmol) dissolved in tetrahydrofuran (5.00 mL) was added in dropwise fashion. The stirring mixture was heated to 45° C. for 26 hours. The reaction was partitioned between ethyl acetate and a saturated ammonium chloride solution, the organic layer washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was dissolved in ethanol (30.0 mL), cooled to 0° C., and treated with sodium borohydride (0.226 g, 6.00 mmol). After 1 hour, the reaction was partitioned between ethyl acetate and a saturated ammonium chloride solution, washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by silica gel chromatography (0-10% ethyl acetate in hexanes) to yield the product as a clear oil (0.953 g, 41%). 1H NMR (500 MHz, CDCl3) δ 5.18-5.04 (m, 3H), 4.23 (ttd, J=7.1, 5.1, 2.6 Hz, 2H), 3.74-3.64 (m, 2H), 2.48-2.40 (m, 1H), 2.25 (ddd, J=8.7, 6.0, 1.5 Hz, 1H), 2.21-2.09 (m, 2H), 2.10-2.00 (m, 8H), 1.97 (dd, J=8.8, 5.5 Hz, 2H), 1.88-1.81 (m, 2H), 1.68 (dt, J=4.2, 1.4 Hz, 6H), 1.60 (dd, J=4.8, 2.6 Hz, 6H), 1.32 (td, J=7.1, 5.3 Hz, 3H), 1.28 (tdd, J=7.1, 2.7, 2.1 Hz, 3H).
(2Z,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol. A mixture of ethyl (2Z,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2E,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate was dissolved in dichloromethane (5.00 mL), cooled to 0° C., and treated, under an argon atmosphere, with diisobutylaluminum hydride (8.00 mL, 8.00 mmol, 1.00 M in heptanes). The reaction was warmed to room temperature and stirred for 22 hours. The reaction was cooled to 0° C., quenched with ethanol (2.00 mL) and stirred vigorously for 24 hours with a solution of sodium potassium tartrate (10.0 g, 35.0 mmol in 50.0 mL water). The mixture was partitioned, and the aqueous layer washed with dichloromethane. The organic layers were combined, dried over sodium sulfate, filtered and concentrated in vacuo to yield the crude product, which was purified by silica gel (1:4 ethyl acetate: hexanes) chromatography to yield (2Z,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol as a mixture of isomers (0.665 g, 80%). 1H NMR (500 MHz, CDCl3) δ 5.17-5.04 (m, 3H), 4.34-4.07 (m, 2H), 3.81-3.69 (m, 2H), 2.19-2.12 (m, 1H), 2.12-2.00 (m, 9H), 1.98 (q, J=7.5, 7.0 Hz, 3H), 1.72-1.65 (m, 9H), 1.63-1.55 (m, 6H), 1.29-1.21 (m, 3H).
{[(2Z,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-yl phosphonato]oxy}phosphonate and {[(2E,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with a mixture of (2Z,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol (0.270 g, 0.830 mmol), dichloromethane (4.00 mL), triethylamine (0.223 mL, 1.60 mmol), cooled to 0° C., and treated with methane sulfonyl chloride (0.0770 mL, 1.00 mmol). The mixture was stirred for 1 hour then quenched with brine and partitioned. The organic layer was washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide crude mixture of (2Z,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-yl methanesulfonate and of (2E,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-yl methanesulfonate (0.374 g). This material was dissolved in acetonitrile (2.00 mL), stirred, and tetrabutylammonium pyrophosphate was added (0.454 g, 0.500 mmol). The reaction mixture was stirred under argon for 2 hours, concentrated and purified over DOWEX50 resin column. The column was prepared with DOWEX50 resin (7.55 g) stirred in concentrated ammonium hydroxide (30.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess buffer 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate was drained from the column and the crude product material applied to the column (dissolved in 3.00 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.141 g, 35%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.52, −10.38 (d, J=22.0 Hz). HRMS ESI [M−H] calc'd=493.2126, observed=493.2130.
Ethyl (2Z,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2E,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate. A 50.0 mL 14/20 round bottom flask was charged with sodium hydride (0.151 g, 4.50 mmol). Under an argon atmosphere at 0° C. was added anhydrous tetrahydrofuran (10.0 mL), followed by triethyl-2-chloro-phosphonoacetate (1.00 g, 3.86 mmol) dissolved in tetrahydrofuran (2.00 mL). Once gas evolution ceased, farnesyl acetone (1.04 g, 4.00 mmol) was added dissolved in tetrahydrofuran (1.00 mL). The mixture was heated to 45° C. for 19 hours, concentrated in vacuo and partitioned between ethyl acetate and a saturated ammonium chloride solution. The organic layer was washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo to provide an oil. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield a mixture of ethyl (2Z,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2E,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate (0.880 g, 62%). NMR (500 MHz, CDCl3) δ 5.19-5.05 (m, 3H), 4.33-4.09 (m, 2H), 2.59-2.51 (m, 1H), 2.49-2.43 (m, 1H), 2.40 (dt, J=8.7, 7.2 Hz, 1H), 2.32-2.24 (m, 1H), 2.22-2.12 (m, 3H), 2.12-1.94 (m, 8H), 1.69 (dt, J=2.7, 1.3 Hz, 6H), 1.66-1.60 (m, 6H), 1.34-1.23 (td, J=7.1, 4.1 Hz, 3H).
(2Z,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol. A 50.0 mL 24/40 round bottom flask was charged with a mixture of ethyl (2Z,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate and ethyl (2E,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraenoate (0.840 g, 2.30 mmol). The material was dissolved in dichloromethane (5.00 mL) and, under an argon atmosphere at 0° C., treated with diisobutylaluminum hydride (7.00 mL, 7.00 mmol, 1.00 M in heptanes). The mixture was warmed to room temperature and stirred for 18 hours, then quenched with ethanol (5.00 mL). A solution of sodium potassium tartrate (7.00 g, 24.8 mmol in 50.0 mL water) was added and the biphasic mixture vigorously stirred for 24 hours. The reaction mixture partitioned, and the aqueous layer twice washed with dichloromethane (20.0 mL per wash). The organic layers were combined, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield a mixture of (2Z,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol (0.220 g, 30%). 1H NMR (500 MHz, CDCl3) δ 5.18-5.06 (m, 3H), 4.29 (d, J=14.7 Hz, 1H), 4.19-3.76 (m, 1H), 2.31-2.19 (m, 1H), 2.17-2.01 (m, 9H), 1.98 (dd, J=9.5, 6.1 Hz, 2H), 1.69 (ddd, J=5.5, 2.6, 1.3 Hz, 9H), 1.64-1.58 (m, 6H). HRMS ESI (+) calc'd for [M+Na]=347.2118, found=347.2159.
{[(2Z,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-yl phosphonato]oxy}phosphonate and {[(2Z,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with a mixture of (2Z,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-chloro-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol. (0.227 g, 0.670 mmol) and anhydrous ether (3.00 mL). At 0° C., under an argon atmosphere, phosphorus tribromide (0.270 g, 1.00 mmol) dissolved in ether (1.00 mL) was added. The mixture was stirred for 2 hours, diluted with hexanes, washed with brine, a saturated sodium bicarbonate solution and brine, then dried over sodium sulfate, filtered, and concentrated in vacuo. To this material dissolved in acetonitrile (1.50 mL) and treated with tetrabutylammonium pyrophosphate (0.504 g, 0.550 mmol). The reaction vessel was sealed and stirred under an argon atmosphere for 2 hours, then concentrated in vacuo to a viscous liquid and purified on DOWEX50 resin column. The resin column was prepared by stirring DOWEX50 resin (7.70 g) in concentrated ammonium hydroxide (30.0 mL) for 20 minutes. The resin was then filtered and washed four times with water (100 mL) and subsequently suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate), then poured into a column. The excess 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude product material applied to the column (dissolved in 3.00 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.177 g, 55%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.17, −10.51. HRMS ESI [M−H] calc'd=483.1474, observed=483.1471.
4-{[dimethyl(phenyl)silyl]oxy}but-2-yn-1-ol. A 250 mL 24/40 round bottom flask was charged with 2-butyne-1,4-diol (2.15 g, 25.0 mmol), tetrahydrofuran (75.0 mL), cooled to 0° C., and treated with sodium hydride (0.840 g, 25.0 mmol). Under an argon atmosphere, phenyldimethylchlorosilane (1.65 mL, 10.0 mmol) was added and the mixture stirred at room temperature for 19 hours, concentrated to a solid, partitioned between ethyl acetate and a saturated ammonium chloride solution, then washed with brine, dried over sodium sulfate, filtered and concentrated to dryness. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield the product (0.320 g, 14%). 1H NMR (500 MHz, CDCl3) δ 7.65-7.57 (m, 2H), 7.46-7.36 (m, 3H), 4.32 (t, J=1.8 Hz, 2H), 4.24 (t, J=2.0 Hz, 2H), 0.46 (s, 6H).
4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-yn-1-ol. A 50 mL 14/20 round bottom flask was charged with trans, trans-farnesol (0.889 g, 4.00 mmol), diethyl ether, (10.0 mL), and at 0° C. (argon atmosphere), treated with phosphorus tribromide (1.35 g, 5.00 mmol) and stirred for 30 minutes. The mixture was then diluted with hexanes, washed with brine, a saturated solution of sodium bicarbonate, and brine. The organic layer was then dried over sodium sulfate, filtered, and concentrated in vacuo to provide crude (6E,10E)-12-bromo-2,6,10-trimethyldodeca-2,6,10-triene (0.523 g, 1.80 mmol). The crude was diluted with tetrahydrofuran (10.0 mL) and charged with 4-{[dimethyl(phenyl)silyl]oxy}but-2-yn-1-ol (0.320 g, 1.30 mmol) and the mixture cooled to 0° C. and treated with sodium hydride (0.122 g, 5.00 mmol). After gas evolution ceased, the mixture (argon atmosphere) was heated to 45° C. for 19 hours. The reaction mixture was partitioned between ethyl acetate and a saturated ammonium chloride solution, the organic layer washed with brine, dried with sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to provide crude dimethyl(phenyl)[(4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-yn-1-yl)oxy]silane (0.394 g, 71%). A 25.0 mL 14/20 round bottom flask was charged with this material and, under an argon atmosphere, tetrabutylammonium fluoride (5.00 mL, 5.00 mmol, 1.00 M solution in tetrahydrofuran) was added and the mixture stirred at 45° C. for 20 hours. The mixture was partitioned between ethyl acetate and 1.00 N HCl (10.0 mL), the organic layer was washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield the product (0.050 g, 18%). 1H NMR (500 MHz, CDCl3) δ 5.45-5.28 (m, 1H), 5.09 (dddt, J=8.4, 7.0, 5.6, 1.4 Hz, 2H), 4.30 (t, J=1.8 Hz, 2H), 4.19-4.11 (m, 2H), 4.06 (d, J=6.9 Hz, 2H), 2.15-2.00 (m, 6H), 2.00-1.91 (m, 2H), 1.73-1.65 (m, 6H), 1.63-1.56 (m, 6H).
[(4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-yn-1-yl phosphonato)oxy]phosphonate. A 10.0 mL 14/20 round bottom flask was charged with 4-{[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}but-2-yn-1-ol (0.050, 0.170 mmol), diethyl ether (1.00 mL), cooled to 0° C., and treated with phosphorus tribromide (0.0280 mL, 0.300 mmol). The mixture was stirred at 0° C. for 15 minutes, diluted with hexanes, washed with brine, a saturated sodium bicarbonate solution, and brine. The organic layer was dried over sodium sulfate and concentrated to provide crude (6E,10E)-12-[(4-bromobut-2-yn-1-yl)oxy]-2,6,10-trimethyldodeca-2,6,10-triene (0.0600 g, 100%). This material was dissolved in acetonitrile (2.00 mL) and, under an argon atmosphere, treated with tetrabutylammonium pyrophosphate (0.251 g, 0.270 mmol), then stirred for 2 hours. The mixture was concentrated to a viscous liquid and purified over DOWEX50 resin column, the column prepared by dissolving DOWEX50 resin (5.98 g) in concentrated ammonium hydroxide (30.0 mL) for 20 minutes, then filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20 mL of 1:49 2-propanol: 25 mmolar ammonium bicarbonate) and poured into the column. The excess buffer was drained from the column and the crude material applied to the column (dissolved in 3.00 mL of the same buffer). The material was eluted with 30.0 mL buffer and lyophilized to a waxy solid (0.076 g, 100%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.46 (d, J=21.5 Hz), -10.18--11.03 (m). HRMS ESI [M−H] calc'd=449.1497, observed=449.1494.
(2Z,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol. A 100 mL 14/20 round bottom flask was charged with ethyl 2-(diethoxyphosphoryl)-2-ethoxyacetate (2.36 g, 8.80 mmol. Prepared according to the method described in Bach, K.; Hesham, R., E.-S.; Jensen, H. M.; Nielsen, H. B.; Thomson, I.; Torssell, K. B. G., Tetrahedron, 1994, 50, 7543), tetrahydrofuran (15.0 mL) then cooled to 0° C., and treated with sodium hydride (0.336 g, 10.0 mmol) under an argon atmosphere. Farnesyl acetone (1.57 g, 6.00 mmol), dissolved in tetrahydrofuran (5.00 mL), was added in dropwise fashion. The mixture was then heated to 45° C. for 26 hours and quenched with a saturated ammonium chloride solution. The reaction was partitioned with ethyl acetate, washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was dissolved in ethanol (30.0 mL) then cooled to 0° C. and treated with sodium borohydride (0.226 g, 6.00 mmol) and the mixture stirred for 1 hour. The mixture was partitioned between ethyl acetate and saturated ammonium chloride solution, washed with brine, dried over sodium sulfate, and concentrated in vacuo to dryness. The crude material was purified by silica gel chromatography (0-10% ethyl acetate in hexanes) to yield an oil (0.953 g, 41%). The crude was dissolved in dichloromethane (5.00 mL), cooled to 0° C., under an argon atmosphere, and treated with diisobutylaluminum hydride (8.00 mL, 8.00 mmol, 1.00 M in heptanes). The reaction was warmed to room temperature, stirred for 22 hours, then cooled to 0° C. and quenched with ethanol. The mixture was then treated with a solution of sodium potassium tartrate (10.0 g, 35.0 mmol in 50.0 mL water) and vigorously stirred for 24 hours. The mixture was partitioned, and the aqueous layer washed with dichloromethane. The organic layers were combined, dried over sodium sulfate, filtered, concentrated in vacuo and purified by silica gel chromatography to yield the product (0.665 g, 80%). 1H NMR (500 MHz, CDCl3) δ 5.17-5.04 (m, 3H), 4.34-4.07 (m, 2H), 3.81-3.69 (m, 2H), 2.19-2.12 (m, 1H), 2.12-2.00 (m, 9H), 1.98 (q, J=7.5, 7.0 Hz, 3H), 1.72-1.65 (m, 9H), 1.63-1.55 (m, 6H), 1.29-1.21 (m, 3H).
{[(6E,10E)-3,7,11,15-tetramethyl-2-oxohexadeca-6,10,14-trien-1-yl phosphonato]oxy} phosphonate. A 25.0 mL 14/20 round bottom flask was charged with (2Z,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol and (2E,6E,10E)-2-ethoxy-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetraen-1-ol (0.385 g, 1.15 mmol), dichloromethane (5.00 mL) and triphenylphosphine (0.314 mL, 1.20 mmol). The mixture was cooled to 0° C. and treated with carbon tetrabromide (0.379 mL, 1.20 mmol dissolved in 1.00 mL dichloromethane). The mixture was stirred for 10 minutes at 0° C. and 20 minutes at room temperature. The mixture was concentrated to ˜1.00 mL in vacuo and diluted with hexanes (15.0 mL). A solid precipitated and the mixture filtered through Celite, this process was repeated twice to yield crude (6E,10E)-1-bromo-3,7,11,15-tetramethylhexadeca-6,10,14-trien-2-one (0.397 g) as an oil. This material was dissolved in acetonitrile (2.00 mL) and treated with tetrabutylammonium pyrophosphate (0.775 g, 0.850 mmol). The reaction mixture was stirred under an argon atmosphere for 2 hours, concentrated in vacuo and purified on a DOWEX50 resin column, the column prepared by first suspending the DOWEX50 resin (11.7 g) in concentrated ammonium hydroxide (45.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate) and loaded into the DOWEX50 column. The excess 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material on the column (dissolved in 3.00 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.291 g, 55%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.10, −10.74. HRMS ESI [M−H] calc'd=465.1813, observed=465.1812.
4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}benzaldehyde. A 25.0 mL 14/20 round bottom flask was charged with geranyl bromide (0.975 g, 4.50 mmol, Brundel, B., J., J., M.; Steen, H.; Heeres, A.; Seerden, J. P. G., WO2013157926), acetone (15.0 mL), 4-hydroxybenzaldehyde (0.732 g, 6.00 mmol) and potassium carbonate (1.10 g, 8.00 mmol). The mixture was stirred overnight, then partitioned between ethyl acetate and a saturated aqueous ammonium chloride solution. The organic layer was then washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by filtration through a triethylamine-deactivated silica (100% ethyl acetate) to yield the pure product (0.980 g, 84%). 1H NMR (500 MHz, CDCl3) δ 9.95-9.82 (m, 1H), 7.90-7.72 (m, 2H), 7.05-6.94 (my, 2H), 5.55-5.42 (m, 1H), 5.13-5.03 (m, 1H), 4.70-4.52 (m, 2H), 2.24-1.99 (m, 4H), 1.79-1.75 (m, 3H), 1.68 (d, J=1.4 Hz, 3H), 1.61 (d, J=1.3 Hz, 3H).
Ethyl (2E)-3-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}phenyl)-2-methylprop-2-enoate and ethyl (2Z)-3-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}phenyl)-2-methylprop-2-enoate. A 50.0 mL 14/20 round bottom flask was charged with 4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}benzaldehyde (0.800 g, 3.10 mmol), tetrahydrofuran (15.0 mL), cooled to 0° C., and treated with sodium hydride (0.201 g, 6.00 mmol) under an argon atmosphere. Triethyl-2-phosphonopropionate (0.952 g, 4.00 mmol), dissolved in tetrahydrofuran (2.00 mL), was added dropwise. After gas evolution ceased, the mixture was heated to 45° C. for 70 hours and quenched with methanol. The mixture was partitioned between ethyl acetate and a saturated ammonium chloride solution, the organic layer washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was dissolved in ethanol (20.0 mL), cooled to 0° C., and sodium borohydride added (0.082 g, 2.10 mmol). After 10 minutes, the reaction was quenched with a saturated ammonium chloride solution (30.0 mL) and partitioned with ethyl acetate. The organic layer was washed with brine, dried over sodium sulfate, filtered and concentrated to dryness. The crude material was purified by silica gel chromatography (0-10% ethyl acetate in hexanes) to yield an oil (0.43 g, 41%). 1H NMR (500 MHz, CDCl3) δ 7.65 (d, J=1.8 Hz, 1H), 7.44-7.34 (m, 2H), 7.00-6.86 (m, 2H), 5.50 (tp, J=6.6, 1.4 Hz, 1H), 5.10 (ddp, J=6.8, 5.4, 1.4 Hz, 1H), 4.62-4.54 (m, 2H), 4.27 (q, J=7.1 Hz, 2H), 2.20-2.01 (m, 7H), 1.76 (t, J=1.3 Hz, 3H), 1.69 (q, J=1.3 Hz, 3H), 1.62 (d, J=1.3 Hz, 3H), 1.36 (t, J=7.1 Hz, 3H).
(2E)-3-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}phenyl)-2-methylprop-2-en-1-ol and (2Z)-3-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}phenyl)-2-methylprop-2-en-1-ol. A mixture of ethyl (2E)-3-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}phenyl)-2-methylprop-2-enoate and ethyl (2Z)-3-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}phenyl)-2-methylprop-2-enoate (0.430, 1.20 mmol) was dissolved in dichloromethane (5.00 mL), cooled to 0° C. under an argon atmosphere, and treated with diisobutylaluminum hydride (3.00 mL, 3.00 mmol, 1.00 M in heptanes). The reaction was allowed to warm to room temperature and stirred for 22 hours, cooled to 0° C., quenched with ethanol (2.00 mL) and stirred vigorously for 24 hours with a solution of sodium potassium tartrate (10.0 g, 35.0 mmol in 40.0 mL water). The mixture was partitioned, the aqueous layer washed with dichloromethane and the organic layers combined, dried over sodium sulfate, filtered, and concentrated in vacuo. The crude was purified by silica gel chromatography to yield an oil (0.240 g, 80%). 1H NMR (500 MHz, CDCl3) δ 7.25-7.19 (m, 2H), 6.93-6.85 (m, 2H), 6.49-6.41 (m, 1H), 5.50 (tq, J=6.6, 1.3 Hz, 1H), 5.10 (ddp, J=7.0, 5.8, 1.4 Hz, 1H), 4.55 (d, J=6.5 Hz, 2H), 4.17 (d, J=1.3 Hz, 2H), 2.20-2.02 (m, 4H), 1.91 (d, J=1.4 Hz, 3H), 1.74 (d, J=1.4 Hz, 3H), 1.69 (d, J=1.4 Hz, 3H), 1.61 (d, J=1.4 Hz, 3H).
{[(2E)-3-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}phenyl)-2-methylprop-2-en-1-yl phosphonato]oxy}phosphonate and {[(2Z)-3-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}phenyl)-2-methylprop-2-en-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with a mixture of (2E)-3-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}phenyl)-2-methylprop-2-en-1-ol and (2Z)-3-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}phenyl)-2-methylprop-2-en-1-ol (0.212 g, 0.570 mmol), diluted in dichloromethane (3.00 mL), cooled to 0° C., and, under an argon atmosphere, treated with phosphorus tribromide (0.0940 mL, 1.00 mmol). The reaction was stirred at 0° C. for 1 hour then diluted with hexanes, quenched with brine, washed with sodium bicarbonate, and brine. The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to provide crude mixture of 1-[{(1E)-3-bromo-2-methylprop-1-en-1-yl]-4-[(2E)-3,7-dimethylocta-2,6-dien-1 -yl]oxy}benzene and 1-[(1Z)-3-bromo-2-methylprop-1-en-1-yl]-4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}benzene (0.216 g, 100%). This material was dissolved in acetonitrile (2.00 mL), then treated with tetrabutylammonium pyrophosphate (0.394 g, 0.430 mmol). The mixture was stirred under an argon atmosphere for 2 hours, at which time it was concentrated in vacuo and purified over DOWEX50 resin column, which was prepared according to the following method. DOWEX50 resin (6.70 g) was stirred in concentrated ammonium hydroxide (30.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.00 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a waxy solid (0.170 g, 65%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.49 (d, J=21.8 Hz), −10.26 (d, J=21.4 Hz). HRMS ESI [M−H] calc'd=459.1343, observed=459.1305.
Ethyl (2E,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaenoate, ethyl (2Z,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaenoate, ethyl (2E,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaenoate, and ethyl (2Z,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaenoate. A 100 mL 14/20 round bottom flask was charged with triethyl-4-phosphonocrotonate (3.00 g, 12.0 mmol), tetrahydrofuran (30.0 mL), cooled to 0° C., and sodium hydride (0.504 g, 15.0 mmol). After gas evolution ceased, a mixture of (2E,6E)-3,7,11-trimethyldodeca-2,6,10-trienal and (2Z,6E)-3,7,11-trimethyldodeca-2,6,10-trienal (2.04 g, 9.20 mmol, Hu, H.; Harrison, T. J.; Wilson, P. D., J. Org. Chem., 2004, 69, 3782.) was added as a solution in tetrahydrofuran (2.00 mL). After 2 hours the mixture was quenched with a saturated ammonium chloride solution and partitioned into ethyl acetate. The organic layer was washed with brine, dried over sodium sulfate, filtered, concentrated in vacuo, and purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to provide an oil (1.64 g, 56%). 1H NMR (500 MHz, Chloroform-d) δ 7.35 (dddd, J=15.2, 11.3, 6.9, 0.8 Hz, 1H), 6.85-6.76 (m, 1H), 6.21 (dt, J=14.7, 10.7 Hz, 1H), 5.96 (dd, J=11.3, 2.0 Hz, 1H), 5.82 (dd, J=15.2, 2.0 Hz, 1H), 5.18-5.04 (m, 2H), 4.20 (q, J=7.1 Hz, 2H), 2.28-2.10 (m, 4H), 2.09-2.03 (m, 2H), 2.01-1.93 (m, 2H), 1.85 (dd, J=9.4, 1.3 Hz, 3H), 1.68 (d, J=1.6 Hz, 3H), 1.60 (dd, J=4.4, 2.8 Hz, 6H), 1.30 (t, J=7.1 Hz, 3H).
(2E,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-ol, (2Z,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-ol, (2E,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-ol, and (2Z,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-ol. A mixture of ethyl (2E,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaenoate, ethyl (2Z,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaenoate, ethyl (2E,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaenoate, and ethyl (2Z,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaenoate (1.64 g, 5.1 mmol) was dissolved in dichloromethane (10.0 mL), cooled to 0° C. under an argon atmosphere, and diisobutylaluminum hydride added (15.0 mL, 15.0 mmol, 1.00 M in heptanes). The mixture was warmed to room temperature and stirred for 22 hours. The reaction was cooled to 0° C., quenched with ethanol (2.00 mL) and stirred vigorously for 24 hours with a solution of sodium potassium tartrate (10.0 g, 35.0 mmol in 40.0 mL water). The reaction mixture was partitioned, and the aqueous layer washed with dichloromethane. The organic layers were combined, dried over sodium sulfate and concentrated in vacuo to provide the crude product mixture, which was purified by silica gel chromatography (1:9 ethyl acetate: hexanes) to yield a mixture of the products (0.610 g, 44%). 1H NMR (500 MHz, CDCl3) δ 6.50-6.40 (m, 1H), 6.36-6.26 (m, 1H), 6.13 (dt, J=14.8, 10.7 Hz, 1H), 5.91-5.85 (m, 1H), 5.80 (ddd, J=15.2, 7.3, 5.0 Hz, 1H), 5.10 (dtdq, J=9.9, 7.0, 2.9, 1.4 Hz, 2H), 4.20 (dd, J=6.0, 1.4 Hz, 2H), 2.20-2.09 (m, 6H), 1.98 (dd, J=9.2, 6.1 Hz, 2H), 1.80 (dd, J=14.2, 1.3 Hz, 3H), 1.68 (t, J=1.4 Hz, 3H), 1.60 (d, J=1.3 Hz, 6H). HRMS ESI (+) calc'd for [M+Na]=297.2195, found=297.2242.
{[(2E,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-yl phosphonato]oxy}phosphonate, {[(2Z,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-yl phosphonato]oxy}phosphonate, {[(2E,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-yl phosphonato]oxy}phosphonate, {[(2Z,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-yl phosphonato]oxy}phosphonate. A 25.0 mL 14/20 round bottom flask was charged with a mixture of (2E,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-ol, (2Z,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-ol, (2E,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-ol, and (2Z,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-ol (0.164 g, 0.590 mmol) was dissolved in diethyl ether (3.00 mL) and under an argon atmosphere at 0° C., treated with triethylamine (0.208 mL, 1.50 mmol) followed by methanesulfonyl chloride (0.0770 mL, 1.00 mmol). A precipitate formed upon the addition and after 30 minutes at 0° C., the reaction was diluted with hexanes and washed with brine (three times), the organic layer dried over sodium sulfate, and concentrated in vacuo to yield the crude (2E,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-yl methanesulfonate, (2Z,4E,6E,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-yl methanesulfonate, (2E,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-yl methanesulfonate, and (2Z,4E,6Z,10E)-7,11,15-trimethylhexadeca-2,4,6,10,14-pentaen-1-yl methanesulfonate (0.211 g, 100%). This mixture was dissolved in acetonitrile (2.00 mL) and treated with tetrabutylammonium pyrophosphate (0.332 g, 0.360 mmol). The reaction mixture was stirred under argon for 2 hours, at which time it was concentrated in vacuo and purified over DOWEX50 resin column. The column was prepared via the following method. DOWEX50 resin (6.7 g) was stirred in concentrated ammonium hydroxide (30.0 mL) for 20 minutes. The resin was filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propanol: 25.0 mmolar ammonium bicarbonate) and poured into a column. The excess buffer was drained from the column and the crude material was applied to the column (dissolved in 3.0 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a solid (0.127 g, 50%). 31P NMR (202 MHz, Deuterium Oxide) δ −5.88-−6.54 (m), −21.17--21.93 (m). HRMS ESI [M−H] calc'd=433.1550, observed=433.1552.
[2-({[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}methyl)cyclopropyl]methanol. A 50.0 mL 14/20 round bottom flask was charged with trans, trans-farnesol (0.889 g, 4.00 mmol), diethyl ether (10.0 mL), and cooled to 0° C. (argon atmosphere). Phosphorus tribromide (1.35 g, 5.00 mmol) was added and the mixture allowed to stir for 1 hour, then diluted with hexanes, washed with brine, a saturated sodium bicarbonate solution, and then a second time with brine. The organic layer was dried over sodium sulfate and concentrated in vacuo to yield crude trans, trans-farnesyl bromide (1.06 g, 3.7 mmol). 1H NMR (500 MHz, Chloroform-d) δ 4.13-4.04 (m, 2H), 3.40 (s, 2H), 3.29-3.19 (m, 2H), 1.37-1.25 (m, 2H), 0.79 (td, J=8.2, 5.1 Hz, 1H), 0.20 (q, J=5.3 Hz, 1H). A separate flask was charged with [2-(hydroxymethyl)cyclopropyl]methanol (0.612 g, 6.0 mmol, (Ito, M.; Osaku, A.; Shiibashi, A.; Ikariya, T., Org. Lett, 2007, 9, 1821. and tetrahydrofuran (15.0 mL). The mixture was cooled to 0° C. and sodium hydride added (0.268 g, 8.0 mmol). After gas evolution ceased, a solution of crude trans, trans-farnesyl bromide dissolved in tetrahydrofuran (5.0 mL) was added and the mixture heated to 45° C. for 19 hours under an argon atmosphere. The mixture was partitioned between ethyl acetate and a saturated ammonium chloride solution and the organic layer washed with brine and concentrated to dryness to provide an oil. The crude material was purified by silica gel chromatography (1:4 ethyl acetate: hexanes) to yield the product as an oil (0.610 g, 33%). HRMS ESI [M+Na] calc'd=329.2457, observed=329.2474.
[2-([{(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}methyl)cyclopropyl]methanol (0.200 g, 0.650 mmol) was dissolved in diethyl ether (3.00 mL), cooled to 0° C. and under an argon atmosphere, charged phosphorus tribromide (0.270 g, 1.00 mmol) and stirred for 15 minutes. The reaction was diluted with hexanes, washed with brine, a saturated sodium bicarbonate solution, and brine. The organic layer was dried over sodium sulfate and concentrated in vacuo to yield crude 1-(bromomethyl)-2-({[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]oxy}methyl) cyclopropane (0.110 g, 45%). This material was dissolved in acetonitrile (2.00 mL) and tetrabutylammonium pyrophosphate was added (0.221 g, 0.240 mmol), the reaction under an argon atmosphere for two hours. The mixture was then concentrated in vacuo and purified on a DOWEX50 resin column. The DOWEX50 resin (7.30 g) was stirred in concentrated ammonium hydroxide (30.0 mL) for 20 minutes, then filtered and washed four times with water (100 mL). The resin was suspended in a buffer (20.0 mL of 1:49 2-propano1:25.0 mmolar aqueous ammonium bicarbonate) and poured into a column. The excess 1:49 2-propano1:25.0 mmolar aqueous ammonium bicarbonate buffer was drained from the column and the crude material was applied to the column (dissolved in 3.00 mL of the 1:49 2-propanol:25.0 mmolar aqueous ammonium bicarbonate buffer). The material was eluted with 30.0 mL of the 1:49 2-propanol: 25.0 mmolar aqueous ammonium bicarbonate buffer and lyophilized to a solid (0.113 g, 38%). 31P NMR (202 MHz, Deuterium Oxide) δ −6.32 (d, J=20.7 Hz), −10.20 (d, J=20.6 Hz). HRMS ESI [M=H] calc'd=465.1813, observed=465.1808.
Enzymes Coleus forskohlii CfTPS2 (SEQ ID NO:69) and Salvia sclarea SsSCS (SEQ ID NO:61) were coupled in an in vitro assay to ascertain whether the synthetic unnatural methyl-GGDP (C21) substrate can efficiently yield the corresponding C21 methyl-diterpene. The C21 substrate does not exist in nature and has the following structure.
As illustrated in
Many of the foregoing Examples illustrate that single step class I enzymes or single step class II labdane-type enzymes can synthesize irregular type diterpenes and unnatural derivatives thereof. However, this Example demonstrates that modules consisting of coupled class II and class I enzymes can be used in function sequential conversion reaction to prepare new types of diterpenes.
All patents and publications referenced or mentioned herein are indicative of the levels of skill of those skilled in the art to which the invention pertains, and each such referenced patent or publication is hereby specifically incorporated by reference to the same extent as if it had been incorporated by reference in its entirety individually or set forth herein in its entirety. Applicants reserve the right to physically incorporate into this specification any and all materials and information from any such cited patents or publications.
The following statements are intended to describe and summarize various features of the invention according to the foregoing description provided in the specification and figures.
1. A compound of the formula (I) or (II):
wherein:
2. A compound of Statement 1, wherein the compound of the formula (I) is a compound of the formula:
3. A compound of Statement 1, wherein the compound of the formula (II) is a compound of the formula:
4. The compound of any preceding Statement, wherein if X1 is a heteroatom, the heteroatom is oxygen.
5. The compound of any preceding Statement, wherein X3 is oxygen or C1-C5 alkyl, such as —CH2— and C2-C3-alkyl.
6. The compound of any preceding Statement, wherein R3—R6 are each H or C1-C5-alkyl, such as methyl and C2-C3-alkyl.
7. The compound of any preceding Statement, wherein R3 and R5 are each H or C1-C5-alkyl, such as methyl and C2-C3-alkyl; and R4 and R6 are each H.
8. The compound of any preceding Statement, wherein m is 1 or 2.
9. The compound of any preceding Statement, wherein, m is 0.
10. The compound of any preceding Statement, wherein X2 is an alkenyl group of the formula:
or an acyl group of the formula:
11. The compound of any preceding Statement, wherein the compound is a compound of the formula:
12. The compound of any preceding Statement, wherein the compounds can be enzymatically transformed into a terpenoid.
13. The compound of any preceding Statement, wherein the terpenoid comprises a compound core of the formula:
and derivatives thereof, wherein derivatives can comprise additional double bonds, alkyl groups, hydroxy groups, acyl groups, and the like, dispersed about the cores.
14. A method comprising contacting an unnatural substrate with one or more enzymes capable of synthesizing a terpene to generate a primary product.
15. The method of Statement 14, wherein the unnatural substrate is a compound of Statements 1-14.
16. The method of Statement 14, wherein the one or more enzymes are from species Tripterygium wilfordii (Tw), Euphorbia peplus (Ep), Coleus forskohlii (Cf), Ajuga reptans (Ar), Perovskia atriciplifolia (Pa), Nepeta mussini (Nm), Origanum majorana (Om), Hyptis suaveolens (Hs), Grindelia robusta (Gr), Leonotis leonurus (Ll), Marrubium vulgare (Mv), Vitex agnus-castus (Vac), Euphorbia peplus (Ep), Ricinus communis (Rc), Daphne genkwa (Dg), or Zea mays (Zm).
17. The method of Statement 14, wherein the enzyme is from species Salvia sclarea, Coleus forskohlii, Euphorbia peplus, Ajuga reptans, Origanum majoranum, Marrubium vulgare, or Kitasatospora griseola.
18. The method of Statement 14-17, wherein the primary product is a terpenoid.
19. The method of Statement 14-18, wherein one or more of the enzymes has at least 90% sequence identity to SEQ ID NO: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 41, 43, 45, 47, 49, 51, 53, 57, 59, 61, 63, 64, 65, 66, 67, or 69.
20. The method of Statement 14-18 or 19, further comprising contacting the primary product with one or more second enzymes.
21. The method of Statement 14-20, further comprising generating a second product by one or more second enzymes, where the one or more second enzymes catalyze the formation of the second product by using the primary product as a substrate.
22. The method of Statement 20 or 21, wherein the one or more second enzymes at least one of oxidizes, reduces, acylates, and glycosylates the primary product.
23. The method of Statement 20, 21 or 22, wherein the one or more second enzymes is an enzyme listed in Table 2.
24. The method of Statement 20-22 or 23, wherein one or more of the second enzymes has at least 90% sequence identity to SEQ ID NO: 39, 68, 70, or 71.
25. The method of Statement 22-23 or 24, wherein the one or more second enzymes is Cytochrome P450 or a sclareol synthase.
26. The method of Statement 14-23 or 24, which is performed in vitro in a cell-free mixture.
27. The method of Statement 14-23 or 24, which is performed within a cell that expresses the enzyme.
28. A compound of the formula (I)-(IV):
wherein:
29. The compound of Statement 28, wherein X2 is an alkenyl group of the formula:
wherein q is an integer from 1 to 3; or
or an acyl group of the formula:
30. The compound of Statement 28 or 29, wherein the compound is a compound of the formula:
The specific methods, devices and compositions described herein are representative of preferred embodiments and are exemplary and not intended as limitations on the scope of the invention. Other objects, aspects, and embodiments will occur to those skilled in the art upon consideration of this specification, and are encompassed within the spirit of the invention as defined by the scope of the claims. It will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention.
The invention illustratively described herein suitably may be practiced in the absence of any element or elements, or limitation or limitations, which is not specifically disclosed herein as essential. The methods and processes illustratively described herein suitably may be practiced in differing orders of steps, and the methods and processes are not necessarily restricted to the orders of steps indicated herein or in the claims.
Under no circumstances may the patent be interpreted to be limited to the specific examples or embodiments or methods specifically disclosed herein. Under no circumstances may the patent be interpreted to be limited by any statement made by any Examiner or any other official or employee of the Patent and Trademark Office unless such statement is specifically and without qualification or reservation expressly adopted in a responsive writing by Applicants.
The terms and expressions that have been employed are used as terms of description and not of limitation, and there is no intent in the use of such terms and expressions to exclude any equivalent of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention as claimed. Thus, it will be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims and statements of the invention.
The invention has been described broadly and generically herein. Each of the narrower species and subgeneric groupings falling within the generic disclosure also form part of the invention. This includes the generic description of the invention with a proviso or negative limitation removing any subject matter from the genus, regardless of whether or not the excised material is specifically recited herein. In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group.
This application is U.S. National Stage Filing under 35 U.S.C. 371 of International Patent Application No. PCT/US2020/059144, filed Nov. 5, 2020, and published WO 2021/092200 A1 on May 14, 2021, which claims the benefit of U.S. Provisional Patent Appl. Ser. No. 62/930,898, filed Nov. 5, 2019, which is incorporated by reference as if fully set forth herein. Incorporation by Reference of Sequence Listing Provided as a Text File A Sequence Listing is provided herewith as a text file, “2089186.txt” created on Nov. 5, 2020 and having a size of 303,104 bytes. The contents of the text file are incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/059144 | 11/5/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62930898 | Nov 2019 | US |
