Patent Application
20250171482
Nicotinamide riboside (NR) and its reduced form, dihydronicotinamide riboside (NRH), are bioactive molecules under investigation for various biomedical and pharmaceutical uses. However, both materials suffer from some synthetic and stability limitations. In terms of production, existing NR and NRH syntheses use large molar equivalency of protic solvents for which either acidic or basic conditions are applied to assist in the removal of acetate groups present on the nucleoside following glycosylation of the tetraacetate riboside or the chlorotriacetate riboside by nicotinamide (NAM). These conditions complicate the synthesis of NR and NRH, making the production of these compounds costly, generating hazardous byproducts, and requiring technically constraining protocols and safety measures.
The synthesis of several other compounds with acyl-modified carbohydrate moiety suffers from similar problems.
Consequently, there is a need in the art for efficient means to produce compounds with carbohydrate scaffolds under milder and more atom-efficient reaction conditions.
The present disclosure describes a novel reaction that addresses the problems described above by producing compounds with carbohydrate groups through de-acylation in the presence of methanol and a basic amino acid. The reaction appears to generate little or no hazardous byproducts and can be performed under mild conditions of pH and temperature. The deacylation is useful in deesterification and deamidation, among other applications.
A method of deacylating an acylated carbohydrate is provided, the method comprising: (a) forming a reaction mixture by mixing the acylated carbohydrate with a basic amino acid and methanol; and (b) allowing the methanol to react with an acyl group of the acylated carbohydrate.
A method of deacylating a heteroaromatic-aryl amide is provided, the method comprising: (a) forming a reaction mixture by mixing the heteroaromatic-aryl amide with a basic amino acid and methanol; and (b) allowing the methanol to react with an amide group of the heteroaromatic-aryl amide.
A method of producing a deacylated carbohydrate from a corresponding acylated carbohydrate is provided, the method comprising: (a) forming a reaction mixture by mixing the acylated carbohydrate with a basic amino acid and methanol; and (b) allowing the methanol to react with the acylated carbohydrate under conditions sufficient to form the deacylated carbohydrate.
A method of producing a deacylated heteroaromatic amine from a corresponding heteroaromatic amide is provided, the method comprising: (a) forming a reaction mixture by mixing the heteroaromatic amide with a basic amino acid and methanol; and (b) allowing the methanol to react with the heteroaromatic amide under conditions sufficient to form the deacylated heteroaromatic amine.
A method of producing a composition of a basic amino acid and a deacylated carbohydrate is provided, the method comprising: (a) forming a reaction mixture by mixing an acylated carbohydrate with a basic amino acid and methanol; (b) allowing the methanol to react with the acylated carbohydrate under conditions sufficient to form the deacylated carbohydrate and a methyl ester; and (c) removing unreacted methanol from the reaction mixture.
A method of producing a composition of a basic amino acid and a deacylated heteroaromatic amine is provided, the method comprising: (a) forming a reaction mixture by mixing a heteroaromatic amide with a basic amino acid and methanol; (b) allowing the methanol to react with the heteroaromatic amide under conditions sufficient to form the deacylated heteroaromatic amine and a methyl ester; and (c) removing unreacted methanol from the reaction mixture.
A reaction mixture is provided, comprising a basic amino acid, an acylated carbohydrate, and methanol.
A reaction mixture is provided, comprising a basic amino acid, a heteroaromatic amide, and methanol.
A composition comprising a basic amino acid and a deacylated carbohydrate is provided that is the product of any one of the processes above.
A composition comprising a basic amino acid and a deacylated heteroaromatic amine is provided that is the product of any one of the processes above.
In any of the foregoing embodiments, the reaction mixture further comprises water. In some embodiments, the reaction mixture comprises methanol and water at a ratio of about 1:10 to about 1:1.
The above presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key or critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
The present disclosure can be better understood, by way of example only, with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other, emphasis instead being placed upon clearly illustrating the principles of the disclosure.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art of this disclosure. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well known functions or constructions may not be described in detail for brevity or clarity.
The terms “about” and “approximately” shall generally mean an acceptable degree of error or variation for the quantity measured given the nature or precision of the measurements. Typical, exemplary degrees of error or variation are within 20 percent (%), preferably within 10%, more preferably within 5%, and still more preferably within 1l % of a given value or range of values. Numerical quantities given in this description are approximate unless stated otherwise, meaning that the term “about” or “approximately” can be inferred when not expressly stated.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well (i.e., “at least one” of what is described), unless the context clearly indicates otherwise. In every case, use of singular articles and pronouns should be interpreted to support claims to at least one of what is described, and to support claims to exactly one of what is described.
The terms “first”, “second”, and the like are used herein to describe various features or elements, but these features or elements should not be limited by these terms. These terms are only used to distinguish one feature or element from another feature or element. Thus, a first feature or element discussed below could be termed a second feature or element, and similarly, a second feature or element discussed below could be termed a first feature or element without departing from the teachings of the present disclosure.
Terms such as “at least one of A and B” should be understood to mean “only A, only B, or both A and B.” The same construction should be applied to longer list (e.g., “at least one of A, B, and C”).
Terms such as “comprising,” “including,” and “having” shall be interpreted inclusively and in an open fashion, so as not to exclude unlisted elements. Stated another way, such terms imply “not limited to” unless the context explicitly states otherwise.
The term “consisting essentially of” means that, in addition to the recited elements, what is claimed may also contain other elements (steps, structures, ingredients, components, etc.) that do not materially affect the basic and novel characteristic(s) of the claimed invention. This term excludes such other elements that materially affect the basic and novel characteristic(s) of what is claimed for its intended purpose as stated in this disclosure, even if such other elements might enhance the operability of what is claimed for some other purpose.
As used herein, the term “alkyl”, whether used alone or as part of a substituent group, includes straight hydrocarbon groups comprising from one to twenty carbon atoms. Thus, the phrase includes straight chain alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl and the like. The phrase also includes branched chain isomers of straight chain alkyl groups, including but not limited to, the following which are provided by way of example: —CH(CH3)2, —CH(CH3)(CH2CH3), —CH(CH2CH3)2, —C(CH3)3, —C(CH2CH3)3, —CH2CH(CH3)2, —CH2CH(CH3)(CH2CH3), —CH2CH(CH2CH3)2, —CH2C(CH3)3, —CH2C(CH2CH3)3, —CH(CH3)CH(CH3)(CH2CH3), —CH2CH2CH(CH3)2, —CH2CH2CH(CH3)(CH2CH3), —CH2CH2CH(CH2CH3)2, —CH2CH2C(CH3)3, —CH2CH2C(CH2CH3)3, —CH(CH3)CH2CH(CH3)2, —CH(CH3)CH(CH3)CH(CH3)CH(CH3)2, —CH(CH2CH3)CH(CH3)CH(CH3)(CH2CH3), and others. The phrase also includes cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl and such rings substituted with straight and branched chain alkyl groups as defined above. The phrase also includes polycyclic alkyl groups such as, but not limited to, adamantyl norbornyl, and bicyclo[2.2.2]octyl and such rings substituted with straight and branched chain alkyl groups as defined above.
As used herein, the term “alkenyl”, whether used alone or as part of a substituent group, includes an alkyl group having at least one double bond between any two adjacent carbon atoms.
As used herein, the term “alkynyl”, whether used alone or as part of a substituent group, includes an alkyl group having at least one triple bond between any two adjacent carbon atoms.
As used herein, the term “unsubstituted alkyl” refers to alkyl groups that do not contain substituents (atom or group other than hydrogen).
As used herein, the term “substituted alkyl” refers to alkyl groups as defined above in which one or more bonds to a carbon(s) or hydrogen(s) are replaced by a bond to a substituent (atom or group other than hydrogen) such as, but not limited to, an oxygen atom in groups such as hydroxy groups, alkoxy groups and aryloxy groups; a sulfur atom in groups such as, alkyl and aryl sulfide groups, sulfone groups, sulfonyl groups, and sulfoxide groups; a silicon atom in groups such as in trialkylsilyl groups, dialkylarylsilyl groups, alkyldiarylsilyl groups, and triarylsilyl groups; other heteroatoms; and other organic moieties.
As used herein, the term “unsubstituted aralkyl” refers to unsubstituted alkyl or alkenyl groups as defined above in which a hydrogen or carbon bond of the unsubstituted or substituted alkyl or alkenyl group is replaced with a bond to a substituted or unsubstituted aryl group as defined above. For example, methyl (CH3) is an unsubstituted alkyl group. If a hydrogen atom of the methyl group is replaced by a bond to a phenyl group, such as if the carbon of the methyl were bonded to a carbon of benzene, then the compound is an unsubstituted aralkyl group (i.e., a benzyl group).
As used herein, the term “substituted aralkyl” has the same meaning with respect to unsubstituted aralkyl groups that heteroatom-substituted aryl groups had with respect to unsubstituted aryl groups. However, a substituted aralkyl group also includes groups in which a carbon or hydrogen bond of the alkyl part of the group is replaced by a bond to a non-hydrogen atom.
As used herein, the term “unsubstituted heterocyclylalkyl” refers to unsubstituted alkyl or alkenyl groups as defined above in which a hydrogen bond of the unsubstituted alkyl or alkenyl group is replaced with a bond to a substituted or unsubstituted heterocyclyl group. For example, methyl (CH3) is a heteroatom-unsubstituted alkyl group. If a hydrogen atom of the methyl group is replaced by a bond to a heterocyclyl group, such as if the carbon of the methyl were bonded to carbon 2 of pyridine (one of the carbons bonded to the N of the pyridine) or carbons 3 or 4 of the pyridine, then the compound is an unsubstituted heterocyclylalkyl group.
As used herein, the term “substituted heterocyclylalkyl” has the same meaning with respect to unsubstituted heterocyclylalkyl groups that substituted aryl groups had with respect to unsubstituted aryl groups. However, a substituted heterocyclylalkyl group also includes groups in which a non-hydrogen atom is bonded to a heteroatom in the heterocyclyl group of the heterocyclylalkyl group such as, but not limited to, a nitrogen atom in the piperidine ring of a piperidinylalkyl group.
As used herein, the term “unsubstituted heterocyclyl” refers to both aromatic and nonaromatic ring compounds including monocyclic, bicyclic, and polycyclic ring compounds such as, but not limited to, quinuclidyl, containing 3 or more ring members of which one or more is a heteroatom such as, but not limited to, N, O, and S. Although the phrase “unsubstituted heterocyclyl” includes condensed heterocyclic rings such as benzimidazolyl, it does not include heterocyclyl groups that have other groups such as alkyl or halo groups bonded to one of the ring members, as compounds such as 2-methylbenzimidazolyl are “substituted heterocyclyl” groups as defined below.
As used herein, the term “substituted heterocyclyl” has the same meaning with respect to unsubstituted heterocyclyl groups that substituted alkyl groups had with respect to unsubstituted alkyl groups. However, a substituted heterocyclyl group also includes heterocyclyl groups in which one of the carbons is bonded to one of the non-carbon or non-hydrogen atom, such as, but not limited to, those atoms described above with respect to a substituted alkyl and heteroatom-substituted aryl groups and also includes heterocyclyl groups in which one or more carbons of the heterocyclyl group is bonded to a substituted and/or unsubstituted alkyl, alkenyl or aryl group as defined herein. This includes bonding arrangements in which two carbon atoms of a heterocyclyl group are bonded to two atoms of an alkyl, alkenyl, or alkynyl group to define a fused ring system. Examples, include, but are not limited to, 2-methylbenzimidazolyl, 5-methylbenzimidazolyl, 5-chlorobenzthiazolyl, 1-methyl piperazinyl, and 2-chloropyridyl among others.
As used herein, the term “de-acylation” refers to the removal of an acyl group, and includes de-esterification and de-amidation. Acyl groups include ester and amide groups with regard to de-acylation.
Methods of deacylating acylated carbohydrates are provided with numerous advantages over existing methods. These advantages include mild reaction temperatures, mild reaction pH, and few or no hazardous byproducts (although not all embodiments of the methods described herein will have all of these advantages, and the disclosure of these advantages is not intended to limit the invention to embodiments with any such advantages). In this context, a “carbohydrate” refers to a compound containing at least one carbohydrate moiety. Thus, carbohydrate compounds include such classes of compound as monosaccharides, disaccharides, polysaccharides, glycosides, glycosamines, nucleosides, nucleoside analogs, nucleotides, and nucleotide analogs.
In some embodiments, the methods provided herein are performed with water as a solvent. Water is a particularly advantageous solvent due to its biocompatibility and minimal adverse environmental impact as compared to organic solvents. However, water was believed to be detrimental to the stability of the reaction products described herein. It was therefore surprisingly discovered that the presence of water in the reaction mixture did not substantially degrade the reaction product and provided the additional benefit of significantly increasing reaction speed. See, e.g.,
A method of deacylating an acylated carbohydrate is provided. In a general embodiment, the method comprising mixing the acylated carbohydrate, such as a carbohydrate ester or an amidated carbohydrate, with a basic amino acid and methanol, which results in the methanol to reacting with the acyl group, such as the ester or the amide. Some such embodiments of this method proceed adequately at a temperature of about room temperature or higher. Thus, a deacylated carbohydrate compound is produced from a corresponding acylated carbohydrate.
Some embodiments of the method can be used to produce a composition of a basic amino acid and a carbohydrate compound, i.e., a deacylated carbohydrate. In such embodiments there will typically be remaining byproducts, such as the basic amino acid (e.g., lysine), methanol, a methyl ester, or any combination of the foregoing. In a further step most of the remaining basic amino acid (e.g., lysine), methanol and methyl ester may be removed. In more specific embodiments, the molar fraction of methyl esters, basic amino acid (e.g., lysine), and/or methanol that is removed is independently chosen from at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, and 99%. In a specific embodiment at least one of the methanol, basic amino acid (e.g., lysine), and methyl esters are removed such that there is no detectable residue of them in the composition. In some embodiments, the basic amino acid is in the form of a polymer as described herein, e.g., poly-lysine.
In some embodiments of the method, the basic amino acid is lysine, and thus α- or ε—N-lysine-acetamide (α- or ε—N—Ac-lysine) may be produced as a byproduct. However, the level of α- or ε—N—Ac-lysine in many embodiments of the method is relatively low. In some embodiments of the method the composition contains no more than 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, and 1 ppm w/v α- or ε—N—Ac-lysine. A specific embodiment of the method produces less than 25 ppm w/v of α- or ε—N—Ac-lysine. A further specific embodiment of the method produces less than 15 ppm w/v of α- or ε—N—Ac-lysine. A further specific embodiment of the method produces no detectable α- or ε—N—Ac-lysine. Some embodiments of the method result in a level of α- or ε—N—Ac-lysine that is safe for human or animal consumption. In embodiments where α- or ε—N—Ac-lysine is produced, the method may comprise an additional step to remove α- or ε—N—Ac-lysine.
In certain embodiments, the basic amino acid, e.g., lysine, is a catalyst for the deacylation reaction. In such embodiments, α- or ε—N—Ac-lysine is not formed, and the lysine may be recycled for a further reaction in the same reaction mixture, or the lysine may be removed from the reaction mixture and utilized in another reaction, or the lysine may be retained in the resulting product mixture. In some embodiments, the resulting product mixture forms a composition for human or animal consumption, and the basic amino acid, e.g., lysine, serves as a nutritional supplement in the composition. In some embodiments, the basic amino acid is in the form of a polymer as described herein, e.g., poly-lysine, and the polymer may be removed by filtration as further described herein.
In some embodiments of the method, methyl acetate or methyl acylate may be produced as a byproduct. In some embodiments of the method the composition contains no more than 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, and 1 ppm w/v methyl acetate or methyl acylate. In a further specific embodiment of the method, the composition contains no detectable methyl acetate or methyl acylate. Some embodiments of the method result in a level of methyl acetate or methyl acylate that is safe for human or animal consumption. In embodiments where methyl acetate or methyl acylate is produced, the method may comprise an additional step to remove methyl acetate or methyl acylate.
The method disclosed herein produces no significant amount of acetamide (e.g., N-lysine acetamide) as a byproduct, and therefore has the advantage of increased safety for human and animal consumption, due to acetamide's status as a possible carcinogen. In some embodiments of the method the composition contains no more than 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, and 1 ppm w/v acetamide A specific embodiment of the method produces less than 25 ppm w/v of acetamide. A further specific embodiment of the method produces less than 15 ppm w/v of acetamide. A further specific embodiment of the method produces no detectable acetamide. Some embodiments of the method result in a level of acetamide that is safe for human or animal consumption. Such embodiments of the method may comprise an additional step to remove excess acetamide.
The acylated carbohydrate contains an acyl group on the carbohydrate group. The carbohydrate moiety can be a substituted or unsubstituted CnH2nOn aldoses and ketoses such as those, tetrose, pentose, hexose, heptose, octose, or larger carbohydrates, or part of more complex molecules such as glycosides and nucleosides. Examples of possible acylated pentosides are acylated D-arabinoside, D-lyxoside, D-riboside, D-xyloside, L-arabinoside, L-lyxoside, L-riboside, L-xyloside, D-ribuloside, D-xyluloside, L-ribuloside, and L-xyluloside. In some embodiments, the acylated carbohydrate is a pentose polyester. In further embodiments, the acylated carbohydrate is a pentose monoester. In a specific embodiment, the carbohydrate group is a D-riboside moiety.
In some embodiments of the method, the acylated carbohydrate is an amidated carbohydrate and contains a heteroaromatic amide. The heteroaromatic amide can be an acylated form of a nucleobase, or a hetero-arylamine.
In some embodiments of the method, the acylated carbohydrate contains a heteroaromatic ester. The heteroaromatic ester can be an acylated form of a nucleobase, or a hetero-arylamine.
In some embodiments of the method the acyl group is an alkyl ester or amide. In further embodiments of the method the acyl group is a heteroatom-substituted alkyl, heteroatom-substituted alkenyl, substituted alkynyl, substituted aralkyl, substituted heterocyclylalkyl, substituted heterocyclyl, heteroatom-unsubstituted alkyl, heteroatom-unsubstituted alkenyl, unsubstituted alkynyl, unsubstituted aralkyl, unsubstituted heterocyclylalkyl, and unsubstituted heterocyclyl. In some embodiments the ester a C1-C10 ester. In more specific embodiments the acyl group is an ethyl substituted ester. In more specific embodiments of the methods the acylated carbohydrate is an acetyl ester or amide. Such acetyl esters or amides may have varying degrees of acetylation, such as mono-acetylated, di-acetylated, or tri-acetylated. Such mono-, di-, and tri-acetylated acylated carbohydrates are in some embodiments, e.g., where the carbohydrate comprises at least 5 carbons, acetylated at one or more of the 2, 3′, and 5′ carbons.
The method can be applied to various types of acylated carbohydrates, such as esters and amides. These include acyls of glycosamines, nucleosides, nucleoside analogues and derivatives, nucleotides, nucleotide analogues, pyridinium nucleosides, pyrimidine nucleosides, purine nucleosides, nicotinamide glycosides, fructosides, galactosides, glucosides, glucuronides, rhamnosides, ribosides, ribofuranoses, D-ribofuranoses, and R-ribofuranose. In a specific embodiment of the method the acylated carbohydrate is an acyl of NR; this embodiment has the advantage of producing NR, which is a commercially valuable product. In another specific embodiment of the method, the acylated carbohydrate is an acyl of NRH, which is also a commercial valuable product. In such embodiments various acyl groups may be used, such as acetyl esters of NR and NRH. In a more specific embodiment of the method the acyl group is a triacetyl ester of NR or NRH.
In a specific embodiment of the method the acylated carbohydrate is an N-acylated purine nucleoside. In another embodiment of the method the acylated carbohydrate is an N-acylated pyrimidine nucleoside.
The molar concentration of methanol relative to the molar concentration of the acylated carbohydrate will influence the rate and yield of the reaction. In some embodiments of the method the molar concentration of methanol is advantageously at least the molar concentration of acyl groups in the acylated carbohydrate; such embodiments are expected to have the advantage of providing enough methanol groups to fully react with all of the acyl groups. In further embodiments of the method the molar concentration of methanol exceeds the molar concentration of acyl groups in the acylated carbohydrate. If the acylated carbohydrate compound contains additional acyl groups bound to parts of the molecule other than the glycosyl group, then the molar concentration of methanol may be equal to or greater than the molar concentration of only the acyl groups bound to the glycosyl group.
The reaction may be conducted at a temperature suitable to accomplish the desired reaction rate and to provide the desired level of stability to the reaction products. Some embodiments of the reaction can be conducted at relatively high temperatures. In some embodiments of the method, the reaction is allowed to take place at a temperature greater than or about 4° C. In further embodiments of the method the reaction is allowed to take place at a temperature greater than or about 20° C. In further embodiments of the method the reaction is allowed to take place at a temperature up to 50° C. In a more specific embodiment of the method the reaction is allowed to take place at 40-50, or 45-50° C. In further embodiments of the method the reaction is allowed to take place at about room temperature or higher. In further embodiments of the method the reaction is allowed to take place at about room temperature. In still further embodiments of the method the reaction is allowed to take place at a temperature greater than or about 40° C. These temperatures have the advantage of fast reaction rates and acceptable levels of stability.
In some embodiments, the method is performed at a temperature that allows the reaction to proceed to completion in a desirable timeframe while preventing degradation of the reaction products. As discussed herein, reaction speed is significantly increased when the method is performed with water as solvent (or a component of a solvent), as compared to an organic solvent. Without being bound by theory, the presence of water may contribute to the increased reaction speed by stabilizing the carbonyl intermediate and/or solubilizing the product, thereby favoring the reaction towards product formation. The increased reaction speed advantageously allows the reaction temperature to be decreased, such that the reaction still proceeds to completion while minimizing degradation. Accordingly, in certain embodiments, the method is performed at a temperature of −30° C. to about 60° C. In a further embodiment, the method is performed at a temperature of about −20° C. to about 50° C. In still further embodiments, the method is performed at a temperature of about 0° C. to about 30° C. In still further embodiments, the method is performed at a temperature of about 4° C. to about 25° C. In a specific embodiment, the method is performed at a temperature of about −20° C.
The basic amino acid has a side chain with a pKa of greater than 7.0. In some embodiments of the method the basic amino acid has a side chain with a pKa of greater than 7.5, 8.0, 8.5, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, or 13.0. In a specific embodiment the basic amino acid has a side chain with a pKa of greater than 10.5, such as lysine. In another specific embodiment the basic amino acid has a side chain with a pKa of greater than 12.4, such as arginine.
In some cases, the basic amino acid has a side chain with a high enough pKa to cause the pI of the amino acid to be greater than 7.0. In some cases, the basic amino acid has a side chain with a high enough pKa to cause the pI of the amino acid to be greater than 8.0, 8.5, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, or 11.0. In another specific embodiment the basic amino acid has a side chain with a high enough pKa to cause the pI of the amino acid to be greater than 8.0. In another specific embodiment, the basic amino acid has a side chain with a high enough pKa to cause the pI of the amino acid to be greater than 9.4, such as lysine. In another specific embodiment, the basic amino acid has a side chain with a high enough pKa to cause the pI of the amino acid to be greater than 10.7, such as arginine. The basic amino acid may be any with the properties described above, including the 20 “standard” proteogenic amino acids and nonstandard amino acids. In a specific embodiment of the method, the basic amino acid is selected from lysine and arginine. In a further embodiment, the basic amino acid is poly-lysine.
In some embodiments, the basic amino acid is in the form of a polymer, e.g., comprising monomeric basic amino acid residues. In further embodiments, the polymeric basic amino acid monomeric is formed by coupling or crosslinking basic amino acid residues to a polymer, e.g., a resin such as agarose or a copolymer compound such as divinylbenzene. In embodiments, the basic amino acid is poly-lysine. In some embodiments, the poly-lysine comprises a polymer of lysine residues, which may be polymerized at the α-carbon or the ε-carbon to form α-polylysine or ε-polylysine, respectively. α-polylysine may be comprised of L-lysine or D-lysine residues to form poly-L-lysine or poly-D-lysine. In one embodiment, the ε—NH2 group of lysine catalyzes the deacylation reaction, and thus, the lysine polymer is α-polylysine. In further embodiments, the poly-lysine comprises lysine residues coupled or crosslinked to a polymer, e.g., a resin such as agarose or a copolymer compound such as divinylbenzene. Any form of poly-lysine may be used in the methods described herein, so long as an amine group (e.g., the ε—NH2 group) is capable of catalyzing the deacylation reaction at the specified conditions (e.g., in methanol or a mixture of water and methanol). A polymeric basic amino acid, e.g., poly-lysine, is generally sufficiently large that it can be removed by filtration, which simplifies the purification of the deacylated carbohydrate produced by the method described herein. Accordingly, in embodiments, the method provided herein comprises (a) forming a reaction mixture by mixing an acylated carbohydrate with poly-lysine and methanol; (b) allowing the methanol to react with the acylated carbohydrate; and (c) removing the poly-lysine from the reaction mixture, e.g., by filtration. In a further embodiment, the poly-lysine removed during step (c) is recyclable and may be used in a further reaction, thereby reducing the amount of materials required.
The molar concentration of the basic amino acid will be sufficient to effectively catalyze the reaction. Without wishing to be bound by any hypothesis, it is believed that the basic amino acid catalyzes the transesterification of the acyl group by methanol. If that model is correct, then the method would require that the molar concentration of the basic amino acid will be sufficient to catalyze the methylation of at least some of the acyl groups by methanol. In some embodiments of the method, the basic amino acid is present at a molar concentration greater than a molar concentration of the acylated carbohydrate. In further embodiments of the method, the basic amino acid is present at a molar concentration greater than three times a molar concentration of the acylated carbohydrate. In further embodiments, the basic amino acid is present at a molar concentration greater than a molar concentration of acyl groups in the acylated carbohydrate. In embodiments where the basic amino acid is in polymer form, the molar number of monomeric units in the basic amino acid polymer is greater than a molar concentration of acyl groups in the acylated carbohydrate.
Other reaction conditions should be controlled to prevent degradation of the reaction products and maintenance of a sufficiently high reaction rate. For example, in some embodiments of the method it is advantageous to exclude oxygen in solvents to reduce the degradation of NRH to NR and use anhydrous conditions to reduce the degradation of NR to NAM. Accordingly, some embodiments of the method are conducted under conditions of low oxygen. In some such embodiments, the partial pressure of 02 is below 0.20, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08, 0.07, 0.06, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01 atm. In further embodiment reaction conditions are anoxic. In some embodiments of the method, it is advantageous to exclude water vapor to reduce the degradation of NR to NAM. Accordingly, some embodiments of the method are conducted under conditions of low moisture. In some such embodiments, moisture content is below 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 ppm w/w. In a further embodiment, reaction conditions are anhydrous. In a specific embodiment of the method, the reaction is conducted under anhydrous and anoxic conditions.
In a further embodiment of the method, the reaction mixture comprises water. As discussed herein, water was surprisingly discovered to be a suitable solvent for the reaction with minimal product degradation. In embodiments, the reaction mixture comprises methanol and water at a ratio of about 1:30 to about 1:1, or about 1:25 to about 1:1, or about 1:20 to about 1:1, or about 1:15 to about 1:1, or about 1:10 to about 1:1, or about 1:5 to about 1:1, or about 1:4 to about 1:1, or about 1:3 to about 1:1, or about 1:2 to about 1:1. In a specific embodiment, the reaction mixture comprises methanol and water at a ratio of about 1:1.
In some embodiments, the reaction mixture comprises water, e.g., methanol and water at a ratio of about 1:30 to about 1:1, and the method is performed at a temperature of about −30° C. to about 60° C. In a further embodiment, the method is performed at a temperature of about −20° C. to about 50° C. In still further embodiments, the method is performed at a temperature of about 0° C. to about 30° C. In still further embodiments, the method is performed at a temperature of about 4° C. to about 25° C. In an embodiment, the method is performed at a temperature of about −20° C. In a specific embodiment, the reaction mixture comprises methanol and water at a ratio of about 1:1, and the method is performed at a temperature of about −20° C. In embodiments, the reaction is performed in a 1:1 mixture of methanol and water at −20° C., and proceeds to completion (i.e., substantially complete deacylation of the acylated carbohydrate) in less than 5 days, e.g., in 72 hours. As mentioned herein, the reaction proceeds significantly faster in water as compared to organic solvent, which allows the reaction to be conducted at a sufficiently low temperature to avoid product degradation. In embodiments, the reaction in an organic solvent (e.g., 100% methanol) requires at least or about 5 days to complete at room temperature.
In some embodiments, the method produces at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% yield of the deacylated carbohydrate. In a specific embodiment, the reaction mixture comprises methanol and water at a ratio of about 1:1, and the method is performed at a temperature of about −20° C., and the method produces at least 90% or at least 95% yield of the deacylated carbohydrate.
In a further embodiment, the disclosure provides a method of deacylating an acylated carbohydrate, comprising forming a reaction mixture by mixing the acylated carbohydrate, such as a carbohydrate ester or an amidated carbohydrate, with an amine base, such as morpholine, and methanol, which results in the methanol to reacting with the acyl group, such as the ester or the amide. In an embodiment, the amine base, e.g., morpholine, is immobilized, e.g., on a solid support, a resin such as agarose, or a copolymer such as divinylbenzene. In one embodiment, the immobilized morpholine comprises an N-vinylbenzylmorpholine-divinylbenzene copolymer. In a further embodiment, the amine base, e.g., morpholine, is in the form of a polymer, e.g., poly-morpholine. In some embodiments, immobilization of the amine base and/or the amine base being in a polymer form facilitates its removal from the reaction mixture upon reaction completion as described herein.
In some embodiments the reaction mixture consists of water and methanol at the recited ratios as solvents. In other embodiments, the reaction mixture consists essentially of water and methanol as solvents, such that other solvents can also be included, so long as the reaction proceeds to completion at the desired temperature and during the desired time period.
In some embodiments of the method, the basic amino acid and the acylated carbohydrate are actively mixed. Useful mixing methods include stirring, bead-beating, ball-milling, planetary milling, and co-extrusion.
Reaction mixtures are provided that are useful for the methods described above. The reaction mixtures comprise the acylated carbohydrate, basic amino acid, and methanol. The forms of the acylated carbohydrate and amino acid may be any that are described above as useful in the method. The concentrations of acylated carbohydrate, basic amino acid, and methanol may likewise be any that are described above as useful in the method. In a further embodiment, the reaction mixture further comprises water as described herein. In embodiments, the reaction mixture comprises methanol and water at a ratio of about 1:30 to about 1:1, or about 1:25 to about 1:1, or about 1:20 to about 1:1, or about 1:15 to about 1:1, or about 1:10 to about 1:1, or about 1:5 to about 1:1, or about 1:4 to about 1:1, or about 1:3 to about 1:1, or about 1:2 to about 1:1. In a specific embodiment, the reaction mixture comprises methanol and water at a ratio of about 1:1. The reaction mixture can also consist of water and methanol as solvents, or consist essentially of water and methanol as the solvents, as described herein.
A composition containing a carbohydrate compound is provided that is the product of any of the methods described above. The carbohydrate compound is the deacylated version of any of the acylated carbohydrates described as being useful in the method above. The composition may also comprise any basic amino acid described above as suitable for use in the method. In such versions of the composition less than all the basic amino acid has been removed from the reaction products; these embodiments have the advantage of providing a possible nutritional supplement in the form of the amino acid in combination with the carbohydrate compound. In some embodiments of the composition, all or substantially all of the methanol has been removed; these embodiments have the advantage of reducing or eliminating the toxic properties of methanol from the composition. In some embodiments of the composition, all or substantially all of the methyl ester has been removed; these embodiments have the advantage of reducing or eliminating the unwanted properties of methyl ester from the composition. Some embodiments of the composition have a level of acetamide, e.g., N-lysine acetamide, that is safe for consumption. Some embodiments of the composition contain no more than 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, and 1 ppm w/v of acetamide, e.g., N-lysine acetamide. A specific embodiment of the composition contains less than 25 ppm w/v of acetamide, e.g., N-lysine acetamide. A further specific embodiment of the composition contains less than 15 ppm w/v of acetamide, e.g., N-lysine acetamide. A further specific embodiment of the composition contains no detectable acetamide, e.g., N-lysine acetamide. Some embodiments of the composition contain a level of acetamide, e.g., N-lysine acetamide, that is safe for human or animal consumption. Such embodiments of the composition may result from an additional step to remove excess acetamide, e.g., N-lysine acetamide. As discussed above, the composition will in some embodiments have a level of methyl acetate or methyl acylate that is safe for consumption. Some embodiments of the composition contain no more than 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, and 1 ppm w/v methyl acetate or methyl acylate. A specific embodiment of the composition contains less than 25 ppm w/v of methyl acetate or methyl acylate. A further specific embodiment of the composition contains less than 15 ppm w/v of methyl acetate or methyl acylate. A further specific embodiment of the composition contains no detectable methyl acetate or methyl acylate. Some embodiments of the composition contain a level of methyl acetate or methyl acylate that is safe for human or animal consumption. Such embodiments of the composition may result from an additional step to remove excess methyl acetate or methyl acylate. As discussed above, the composition will in some embodiments have no significant amount of acetamide or a level of acetamide that is safe for consumption. In some embodiments of the composition contains no more than 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, and 1 ppm w/v acetamide. A specific embodiment of the composition contains less than 25 ppm w/v of acetamide. A further specific embodiment of the composition contains less than 15 ppm w/v of acetamide. A further specific embodiment of the composition contains no detectable acetamide. Low concentrations of acetamide have the advantage of increased safety for human and animal consumption, due to its status as a possible carcinogen. Some embodiments of the composition contain a level of acetamide that is safe for human or animal consumption. Such embodiments of the composition may result from an additional step to remove excess acetamide.
Embodiment 1 provides a method of deacylating an acylated carbohydrate, the method comprising: (a) forming a reaction mixture by mixing the acylated carbohydrate with a basic amino acid and methanol; and (b) allowing the methanol to react with an acyl group of the acylated carbohydrate.
Embodiment 2 provides a method of producing a deacylated carbohydrate from a corresponding acylated carbohydrate, the method comprising: (a) forming a reaction mixture by mixing the acylated carbohydrate with a basic amino acid and methanol; and (b) allowing the methanol to react with the acylated carbohydrate under conditions sufficient to form the deacylated carbohydrate.
Embodiment 3 provides a method of producing a composition comprising a basic amino acid and a deacylated carbohydrate, the method comprising: (a) forming a reaction mixture by mixing an acylated carbohydrate with a basic amino acid and methanol; (b) allowing the methanol to react with the acylated carbohydrate to form the deacylated carbohydrate and a methyl ester; and (c) removing unreacted methanol from the reaction mixture.
Embodiment 4 includes the method of embodiment 3, further comprising removing the methyl ester from the reaction mixture.
Embodiment 5 includes the method of any one of embodiments 1-4, wherein the method produces less than 25 ppm of methyl ester.
Embodiment 6 includes the method of any one of embodiments 1-5, wherein the method produces no detectable acetamide.
Embodiment 7 includes the method of any one of embodiments 1-6, further comprising removing the basic amino acid from the reaction mixture following step (b).
Embodiment 8 includes the method of any one of embodiments 1-7, wherein the acylated carbohydrate is a pentose poly- or mono-ester.
Embodiment 9 includes the method of any one of embodiments 1-7, wherein the acylated carbohydrate is mono-acetylated, di-acetylated, or tri-acetylated.
Embodiment 10 includes the method of any one of embodiments 1-9, wherein the acylated carbohydrate comprises at least 5 carbons and is acetylated at one or more of its 2′, 3′, and 5′ carbons.
Embodiment 11 includes the method of any one of embodiments 1-10, wherein the acylated carbohydrate is a substituted ester.
Embodiment 12 includes the method of embodiment 11, wherein the acylated carbohydrate is a methyl substituted ester.
Embodiment 13 includes the method of embodiment 11, wherein the acylated carbohydrate is a C1-C10 ester.
Embodiment 14 includes the method of any one of embodiments 1-10, wherein the acylated carbohydrate is an ester of nicotinamide riboside.
Embodiment 15 includes the method of embodiment 14, wherein the acylated carbohydrate is an ester of reduced nicotinamide riboside.
Embodiment 16 includes the method of any one of embodiments 1-10, wherein the acylated carbohydrate is acetylated nicotinamide riboside.
Embodiment 17 includes the method of embodiment 16, wherein the acylated carbohydrate is triacetyl nicotinamide riboside.
Embodiment 18 includes the method of any one of embodiments 1-10, wherein the carbohydrate is a riboside.
Embodiment 19 includes the method of any one of embodiments 1-10, wherein the acylated carbohydrate is a pentose heteroarylamide.
Embodiment 20 includes the method of any one of embodiments 1-10, wherein the carbohydrate is a ribofuranoside compound.
Embodiment 21 includes the method of embodiment 20, wherein the carbohydrate is a D-ribofuranoside compound.
Embodiment 22 includes the method of any one of embodiments 1-10, wherein the carbohydrate is a nucleoside.
Embodiment 23 includes the method of any one of embodiments 1-10, wherein the carbohydrate is nicotinamide riboside.
Embodiment 24 includes the method of embodiment 23, wherein the carbohydrate is reduced nicotinamide riboside.
Embodiment 25 includes the method of any one of embodiments 1-10, wherein the acylated carbohydrate is a carbohydrate ester.
Embodiment 26 includes the method of any one of embodiments 1-7, wherein the acylated carbohydrate is a carbohydrate amide.
Embodiment 27 includes the method of any one of embodiments 1-7, wherein the acylated carbohydrate is a heteroaryl acetamide compound.
Embodiment 28 includes the method of any one of embodiments 1-7, wherein the acylated carbohydrate is a benzamide compound.
Embodiment 29 includes the method of any one of embodiments 1-10, wherein the acylated carbohydrate is a furanoside, and wherein the furanoside is acetylated at one or more of its 2′, 3′, and 5′ carbons.
Embodiment 30 includes the method of any one of embodiments 1-29, wherein a molar concentration of the methanol is at least the molar concentration of acyl groups in the acylated carbohydrate.
Embodiment 31 includes the method of any one of embodiments 1-30, wherein the method is performed at a temperature greater than or equal to 20° C.
Embodiment 32 includes the method of any one of embodiments 1-31, wherein the method is performed at about 20° C. to about 25° C.
Embodiment 33 includes the method of any one of embodiments 1-30, wherein the method is performed at a temperature greater than or equal to 40° C.
Embodiment 34 includes the method of any one of embodiments 1-33, wherein the basic amino acid is lysine.
Embodiment 35 includes the method of any one of embodiments 1-33, wherein the basic amino acid is arginine.
Embodiment 36 includes the method of any one of embodiments 1-35, wherein the basic amino acid is present at a molar concentration greater than or equal to a molar volume of the acylated carbohydrate.
Embodiment 37 includes the method of embodiment 36, wherein the basic amino acid is present at a molar concentration greater than or equal to three times the molar volume of the acylated carbohydrate.
Embodiment 38 includes the method of any one of embodiments 1-37, wherein the reaction is conducted under anhydrous and anoxic conditions.
Embodiment 39 includes the method of any one of embodiments 1-37, wherein the reaction mixture further comprises water.
Embodiment 40 includes the method of embodiment 39, wherein the reaction mixture comprises methanol and water at a ratio of about 1:30 to about 1:1.
Embodiment 41 includes the method of embodiment 39 or 40, wherein the method is performed at a temperature of about −30° C. to about 60° C.
Embodiment 42 includes the method of any one of embodiments 39-41, wherein the method is performed at a temperature of about −20° C. to about 50° C.
Embodiment 43 includes the method of any one of embodiments 39-42, wherein the method is performed at a temperature of about 0° C. to about 30° C.
Embodiment 44 includes the method of any one of embodiments 39-43, wherein the method is performed at a temperature of about 4° C. to about 25° C.
Embodiment 45 includes the method of embodiment 39 or 40, wherein the reaction mixture comprises methanol and water at a ratio of about 1:1, and wherein the method is performed at about −20° C.
Embodiment 46 includes the method of any one of embodiments 39-45, wherein the method produces at least 90% yield of the deacylated carbohydrate.
Embodiment 47 includes the method of any one of embodiments 39-46, wherein the method produces at least 95% yield of the deacylated carbohydrate.
Embodiment 48 includes the method of any one of embodiments 1-47, wherein the basic amino acid catalyzes methylation of the acyl group by methanol.
Embodiment 49 includes the method of any one of embodiments 1-48, comprising mixing the acylated carbohydrate with a basic amino acid and methanol by bead-beating.
Embodiment 50 includes the method of any one of embodiments 1-48, comprising mixing the acylated carbohydrate with a basic amino acid and methanol by stirring.
Embodiment 51 includes the method of any one of embodiments 1-48, comprising mixing the acylated carbohydrate with a basic amino acid and methanol by ball-milling.
Embodiment 52 includes the method of any one of embodiments 1-48, comprising mixing the acylated carbohydrate with a basic amino acid and methanol by co-extrusion.
Embodiment 53 provides a reaction mixture for deacylation of a carbohydrate, the reaction mixture comprising: a basic amino acid, the acylated carbohydrate, and methanol.
Embodiment 54 includes the reaction mixture of embodiment 53, further comprising water.
Embodiment 55 includes the reaction mixture of embodiment 54, comprising methanol and water at a ratio of about 1:10 to about 1:1.
Embodiment 56 provides a composition comprising a basic amino acid and a deacylated carbohydrate that is the product of a process comprising: (a) forming a reaction mixture by mixing an acylated carbohydrate with a basic amino acid and methanol; (b) allowing the methanol to react with the acylated carbohydrate to form the deacylated carbohydrate and a methyl ester; and (c) removing unreacted methanol from the reaction mixture.
Embodiment 57 includes the composition of embodiment 56, wherein the process further comprises removing the methyl ester from the reaction mixture.
Embodiment 58 includes the composition of embodiment 56 or 57, comprising less than 25 ppm of acetamide.
Embodiment 59 includes the composition of any one of embodiments 56-58, comprising no detectable acetamide.
Embodiment 60 includes the composition of any one of embodiments 56-59, comprising no detectable methanol.
Embodiment 61 includes the composition of any one of embodiments 56-60, comprising no detectable methyl ester.
Embodiment 62 includes the composition of any one of embodiments 56-61, wherein the reaction mixture further comprises water.
Embodiment 63 includes the composition of embodiment 62, wherein the reaction mixture comprises methanol and water at a ratio of about 1:10 to about 1:1.
Embodiment 64 includes the composition of any one of embodiments 56-63, wherein the reaction mixture comprises methanol and water at a ratio of about 1:1, and wherein the process is performed at about −20° C.
Embodiment 65 provides a composition formed by the method of any one of embodiments 1-52.
A mixture of uridine-triacetate (1 equiv.) in methanol and lysine (3 equiv.) were stirred at room temperature. After the completion of the reaction, the reaction mixture was distilled off to collect the mixture of deacetylated uridine and lysine.
Nicotinamide riboside triacetate (NRTA) deacetylation was tested with different amino acids such as glycine, histidine, glutamic acid, and arginine in addition to lysine. While the attempts of deacetylation using glycine, glutamic acid, and histidine failed completely, arginine was found to induce partial deacetylation under the same conditions. On the other hand, lysine proved to be more effective for the deacetylation of NRTA. Given the efficiency of deacetylation, lysine was finally selected for the optimization experiments. Experiments were monitored by nuclear magnetic resonance (NMR), and the results are shown in
From early optimization studies, it was found that molar equivalency of lysine is sufficient to carry out the NRTA deacetylation in approximately 15-16 hours at room temperature in polar protic solvents, as shown in
NRTA deacetylation was tested with different amino acids such as glycine, histidine, glutamic acid, and arginine in addition to lysine. These experiments showed lysine to be more effective for the deacetylation of NRTA, with arginine being mildly effective in carrying out the complete deacetylation of NRTA. Experiments were monitored by NMR, and the results are shown in
To begin with, experiments were conducted to determine the amount of lysine required for NRH triacetate (NRHTA) deacetylation. The studies revealed that a quantity of 3 equivalents of lysine is required for the complete deacetylation of NRHTA. If the reaction were to be conducted at room temperature using 3 equivalents of lysine, then the deacetylation of NRHTA would be completed in 3 days (72 hours). However, further studies at elevated temperatures found that deacetylation can be effectively conducted at 45-50° C. without compromising the quality of the product or resulting in the formation of undesired side-products. Methanol was selected as an ideal solvent after considering the solubility of NRHTA and lysine in various solvents.
Keeping in consideration of all the above results, it was concluded that optimum conditions for NRHTA deacetylation are approximately 3 equivalents of lysine and a temperature of 45-50° C. in dry degassed methanol as a solvent.
During the studies, the efficiency of methanolysis catalyzed by lysine to carry out the debenzoylation was evaluated. It was noticed that N-benzoyl-cytidine was debenzoylated very effectively using 3 equivalents of lysine. Debenzoylation was also carried out using 1 equivalent of lysine to check the atom efficiency. Regardless of reaction (whether it is deacetylation or debenzoylation), it was noticed that use of stoichiometric amounts of lysine was inevitable and any less would only enhance the reaction times. Use of excess lysine always had a positive impact on the rate of the reaction, as increases in the lysine equivalents enhanced the rate of the reaction. A table of compounds from the study is shown in Table 1.
N-acetyl-cytidine
Cytidine
Adenosine
Guanosine
Thymidine
Uridine
Guanosine
Guanosine
N-benzoyl-cytidine
Cytidine
The above methodology was extended to other ribose derivatives and a variety of purine and pyrimidine derivatives were deacetylated to render free nucleosides by mere use of lysine and methanol. To a stirred solution of the corresponding acetylated nucleoside (1 equiv.) was added lysine (1-3 equiv.), followed by the addition of anhydrous methanol. The resulting mixture was stirred at 50-70° C. until the complete conversion/deacetylation of the starting material. After the reaction was complete, desired compound was obtained by recrystallization using a mixture of ether and methanol. Solid obtained was dried thoroughly to remove traces of methyl acetate obtained as a side-product and the residual solvent traces. The resulting dry compound was analyzed by 1HNMR, 13CNMR and ESI mass spectrometry. For cytidine: 1H NMR (400 MHz, D2O) ppm: 3.67-3.71 (dd, 2H, J=4.4 Hz, 2.8 Hz), 3.99-4.02 (in, 1H), 4.07-4.10 (t, 1H, J=5.8 Hz), 4.17-4.20 (m, 1H), 5.77 (d, 1H, J=4.0 Hz), 5.93 (d, 1H, 7.5 Hz), 7.72 (d, 1H, J=7.5 Hz). 13CNMR (100 MHz, D2O) ppm: 60.67, 69.2, 73.8, 83.7, 90.2, 96.1, 141.6, 157.6, 166.1. For triacetyl guanosine: 1H NMR (400 MHz, CDCl3) ppm: 13CNMR (100 MHz, CDCl3) ppm: 20.6, 20.8, 20.9, 63.5, 70.7, 72.4, 79.9, 84.8, 117.2, 136.0, 151.5, 154.3, 157.0, 169.7, 169.8, 170.5; Calculated Mass: 409.12; Observed Mass: 409.87; Molecular Formula: C16H19N5O8; (See, for example: Journal of the American Chemical Society (2005), 127(51), 18133-18142, “A Quadruply Hydrogen Bonded Hetero-Complex Displaying High-Fidelity Recognition”, which is incorporated by reference in its entirety herein). For tetra-acetyl guanosine: 1H NMR (400 MHz, D2O) ppm: 13CNMR (100 MHz, CDCl3) ppm: 20.3, 20.5, 20.8, 24.2, 63.1, 70.9, 72.7, 80.0, 87.4, 122.5, 138.4, 147.50, 147.53, 155.4, 169.4, 169.6, 171.4, 172.1; Calculated Mass (M+1): 452.14; Observed Mass: 452.01; Molecular Formula: C18H22N5O9. For guanosine: 1H NMR (400 MHz, DMSO) ppm: 13CNMR (100 MHz, DMSO) ppm: 61.8, 70.8, 74.09, 85.62, 86.79, 117.16, 135.90, 151.74, 154.33, 157.
NRTA deacetylation was tested with different amino acids such as glycine, histidine, glutamic acid, and arginine in addition to lysine. While the attempts of deacetylation using glycine, glutamic acid and histidine failed completely, arginine was found to induce partial deacetylation under the same conditions. Lysine on the other hand, proved to be more effective for the deacetylation of NRTA. Given the efficiency of deacetylation, lysine was finally selected for the optimization experiments. Experiments were monitored by NMR and the results are shown in
For some of the nucleosides (e.g. acetylated uridine), deacetylation was found to be accomplished at room temperature, but the conversion was lengthy, compared to those that were conducted at 50-60° C. In some cases, the expected product did not form at all when the reaction was conducted at room temperature.
From the optimization studies, it was found that 1 equivalent of lysine is sufficient to carry out the NRTA deacetylation in approximately 15-16 h at room temperature in methanol. Although in 6-7 hours, deacetylation appeared to be complete by NMR, the experiment was continued overnight at room temperature to ensure complete consumption of the starting material to NR. As any moisture can potentially be detrimental to the product formation (NR), precautions were taken to minimize or eliminate any traces of moisture by thoroughly drying the reagents and solvents (methanol) before the reaction. During optimization studies for this Example, it was noticed that any trace amount of moisture can result in and/or enhance the degradation of NR to NAM. Considering the solubility of the reaction substrates (NRCl and lysine), methanol was selected as an ideal solvent.
Nuclear magnetic resonance (NMR) spectra were recorded on a Bruker Avance III HD 400 spectrometer (1H, 400.11 and 13C, 100.62 MHz) using residual proton signal (1H) and that of carbon atom (13C) of a deuterated solvent as an internal standard relative to TMS. Column chromatography was performed on silica gel columns using medium pressure liquid chromatography systems (Teledyne) with UV monitoring of eluted fractions (at 280 nm and 350 nm). Analytical TLCs were performed with Merck silica gel 60 F254 plates; visualization of TLCs was accomplished by UV light. High-resolution mass spectrometry (HRMS) spectra were obtained on a LTQ Orbitrap XL Mass Spectrometer (Heated Electrospray (HESI) source, positive polarity, capillary temp 200° C., source voltage 3.0 kV). Amberlite IRA-410, Cl-form, ion exchange resin was purchased from Acros Organics.
All commercial reagents and solvents were purchased from VWR and Oakwood chemicals and used without further purification. Anhydrous dichloromethane (DCM) was obtained leaving DCM over calcinated molecular sieves for more than 72 hours.
Schematics for the deacetylation of nicotinamide riboside triacetate (NRTA) are shown in
NRTA deacetylation was tested with different amino acids such as glycine, histidine, glutamic acid and arginine in addition to lysine. While the attempts of deacetylation using glycine, glutamic acid and histidine failed completely, arginine was found to induce partial deacetylation under the same conditions. Lysine on the other hand, proved to be more effective for the deacetylation of NRTA. Given the facile reactivity of lysine, it became the preferred option for the deacetylation experiments. Experiments were monitored by NMR and the results are shown in
Initial studies on NRTA deacetylation were conducted using lysine hydrate. Since the presence of moisture was believed to be detrimental to the product formation, lysine (97% purity from Oakwood) was used. It is to be noted that there was no significant difference in the deacetylation studies conducted using lysine hydrate and lysine (97% purity). NRTA deacetylation using lysine is shown in
During the optimization studies, it was found that 1 equivalent of lysine is sufficient to carry out the NRTA deacetylation in approximately 15-16 hours at room temperature. Although in 6-7 hours, deacetylation appeared to be complete by NMR, the experiment was continued overnight at room temperature to ensure complete consumption of the starting material to NR.
To enhance the rate of the reaction, experiments were conducted using 3 equivalents of lysine in lieu of 1 equivalent. It was found that further increasing the amount of lysine did not affect the rate of the reaction, so 1 or 3 equivalent of lysine was used for the deacetylation experiments. NRTA deacetylation using 3 equivalents of lysine hydrate is shown in
As moisture can potentially be detrimental to the product formation (NR), precautions were taken to minimize or eliminate any traces of moisture by thoroughly drying the reagents and solvents (methanol) before the reaction. During optimization studies for this Example, it was deemed that any trace amount of moisture could result in and/or enhance the degradation of NR to NAM. Considering the solubility of the reaction substrates (NRCl and lysine), methanol was selected as an ideal solvent. Exemplary studies using methanol as a solvent are shown in
Keeping in mind the reaction conditions required for the deacetylation of NRTA, initial attempts were made to deacetylate NRHTA using 1 equivalent of lysine. However, use of stoichiometric amount of lysine always led to partial deacetylation, and so the ratio of lysine to NRHTA was increased to push the reaction to completion. The studies revealed that a quantity of 3 equivalents of lysine is required for the complete deacetylation of NRHTA. If the reaction were to be conducted at room temperature using 3 equivalents of lysine, then the complete deacetylation would require 3 days (72 hours). The effect of temperature on the rate of reaction was evaluated. In further investigations at elevated temperatures, it was determined that there was a significant difference in the rate of reaction with increased temperature. Results showed that deacetylation could be effectively conducted at 45-50° C. without compromising the quality of the product or resulting in the formation of any undesired side-products as opposed to NR. Methanol was selected as an ideal solvent after considering the solubility of NRHTA and lysine in various solvents.
Keeping in consideration of all the above results, it was concluded that optimum conditions for NRHTA deacetylation require approximately 3 equivalents of lysine, a temperature of 45-50° C., and methanol (degassed) as a solvent. With these optimum conditions in hand, NRHTA deacetylation was conducted, and the reaction was successfully completed overnight. Results are shown in
Insights from the NMR Studies on the Mechanism of Lysine Assisted Deacetylation
After the deacetylation reaction of 2′, 3′, 5′-O-triacetyl uridine with lysine, two intense peaks were noticed around 2.01 ppm and 3.64 ppm corresponding to an acetyl peak and a methoxy peak. These peaks were not linked to either uridine or lysine and suggested the presence of methyl acetate as an impurity resulting from the nucleophilic attack of methanol on the acetyl group catalyzed by the amino acid acting as a base. This is confirmed from studies known in the art and the from the 1HNMR which showed the disappearance of peaks exclusively at 2.01 and 3.44 ppm (with other peaks intact) after the samples had been placed overnight under vacuum. This confirmed the formation of the volatile impurity methyl acetate, as shown in
The procedure for the deprotection/deacetylation of NRTA to NR by lysine is as follows: A clean, dry round bottom flask was degassed and charged with nicotinamide riboside triacetate (1 equiv.) followed by dry methanol and lysine (1 equiv.) at room temperature and the resulting mixture was stirred for 4-5 h until the disappearance of starting material. Reaction progress was monitored by 1HNMR. After the reaction was complete, reaction mixture was evaporated to remove methanol and washed with ether, and dried to afford a mixture of NR and lysine.
The procedure for the deprotection of triacetate-NRH (NRHTA) by amino acids is as follows: A clean, dry round bottom flask was flushed with argon (at least 2 times), followed by the addition of reduced nicotinamide riboside triacetate (NRHTA, 1 equiv.) followed by the addition of dried and degassed methanol and lysine (3 equiv.) under argon. The resulting mixture was stirred under argon at 45-50° C. overnight, and reaction progress was monitored by 1HNMR. After the reaction was complete, supernatant was separated from the solid. Both the solid and supernatant were washed with degassed ether to provide a mixture of NRH and lysine.
The procedure for the deprotection of nucleosides by lysine and methanol is as follows: A clean, dry round bottom flask was flushed with argon (at least 2 times), followed by the addition of the corresponding nucleoside (1 equiv.), lysine (3 equiv.) and anhydrous methanol. The resulting mixture was heated to 50° C. and stirred at the same temperature until the reaction completion. After the reaction was complete, the desired product was collected by recrystallization, dried, and analyzed by NMR.
The reaction involves deprotection of NR triacetate to NR by amino acids in methanol at room temperature, in solution and by milling. Results are shown in
NR-triacetate (triflate or chloride) and reduced NR (NRH) triacetate can be deprotected in methanol (<10-15 equivalents) in presence of basic amino acids (shown in
Deacylation of NRTA was tested in a 1:1 mixture of water and MeOH with 1 or 3 equivalents of lysine and at room temperature (see
Deacylation of various acylated ribosides was tested in a 1:1 mixture of water and methanol (MeOH), as shown in
Microwave irradiation was utilized for the conversion of N-acetyl cytidine to cytidine (
The microwave reaction was also performed in water and methanol separately, and the results at 30 seconds are shown in
Different ratios of water and MeOH, temperatures, and amount of lysine were tested for the conversion of NRTA to NR (
Purification of nucleoside-lysine mixtures is performed as follows. Nucleoside-lysine mixtures, including NRCl-lysine mixtures, is purified by precipitation, recrystallization, and/or chromatography techniques. Chromatography techniques include reversed-phase column liquid chromatography and medium and high pressure liquid chromatography. Alternatively, beads or columns that adsorb lysine is applied to separate lysine from nucleosides, and is applied to NRCl-lysine mixtures (see, e.g., Finkler et al., Journal of Biotechnology 324S (2020):100024; https://doi.org/10.1016/j.btecx.2020.100024).
Poly-lysine, i.e., lysine immobilized on a polymer or polymeric form of lysine as described herein, is tested as a reactant for the deacetylation of nucleosides, using water/methanol as co-reagents, to deprotect nucleosides. The poly-lysine is the immobilized L-lysine from G-Biosciences (catalog number 786-1371) and/or the poly-L-lysine solution from Sigma-Aldrich (P8920). Since poly-lysine is a large polymer, it can be filtered after the reaction is completed to simplify the product purification process. Immobilized lysine renders lysine-free NRCl by filtration of the reaction mixture and removal of excess methanol and water, including the volatile methyl ester. The filtered poly-lysine can be recycled similarly to that of immobilized morpholine, as described in Example XI.
Deacylation of N-acetyl cytidine was tested using immobilized morpholine. The reaction scheme is shown in
Immobilized morpholine was dried and used for another batch. Nearly 85 mg of immobilized morpholine (0.2 mmoles) was obtained, which was recycled (used) to deacetylate another fresh batch.
A mixture of N-acetyl cytidine (59 mg, 0.2 mmoles) and the recycled immobilized morpholine (85 mg, 0.2 mmoles) was stirred in methanol (5 mL) at 80° C. for 24 h in 5 mL of methanol. After deacetylation was complete, reaction mixture was filtered off and the filtrate was evaporated to afford pure cytidine. NMR spectra from the reaction mixture and after filtration are shown in
A comparison of the NMR spectra of cytidine produced using the first batch of immobilized morpholine vs. the second, recycled batch of immobilized morpholine is shown in
It is to be understood that any given elements of the disclosed embodiments of the invention may be embodied in a single structure, a single step, a single substance, or the like. Similarly, a given element of the disclosed embodiment may be embodied in multiple structures, steps, substances, or the like.
The foregoing description and accompanying drawings illustrate and describe certain processes, machines, manufactures, and compositions of matter, some of which embody the invention(s). Such descriptions or illustrations are not intended to limit the scope of what can be claimed, and are provided as aids in understanding the claims, enabling the making and use of what is claimed, and teaching the best mode of use of the invention(s). If this description and accompanying drawings are interpreted to disclose only a certain embodiment or embodiments, it shall not be construed to limit what can be claimed to that embodiment or embodiments. Any examples or embodiments of the invention described herein are not intended to indicate that what is claimed must be coextensive with such examples or embodiments. Where it is stated that the invention(s) or embodiments thereof achieve one or more objectives, it is not intended to limit what can be claimed to versions capable of achieving all such objectives. Any statements in this description criticizing the prior art are not intended to limit what is claimed to exclude any aspects of the prior art.
Additionally, the disclosure shows and describes certain embodiments of the processes, machines, manufactures, compositions of matter, and other teachings disclosed. Still, it is to be understood that the teachings of the present disclosure are capable of use in various other combinations, modifications, and environments and are capable of changes or modifications within the scope of the teachings as expressed herein.
Any section headings herein are provided only for consistency with the suggestions of 37 C.F.R. § 1.77 or to provide organizational queues. These headings shall not limit or characterize the invention(s) set forth herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2023/064099 | 3/10/2023 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63319307 | Mar 2022 | US |
