Patent Application
20220204464
Organofluorine chemistry plays an important role in medicinal, agricultural, and material sciences and fields. Fluoroalkyl groups have strong effects such as high stability and lipophilicity, in addition, longer fluoroalkyl groups have high water and oil resistance and low friction.
Loy, R N., et al., Organic Letters 2011, 13, 2548-2551, discloses Pd-catalyzed coupling of CF3—I with benzene in 26% GC yield.
According to Table 1 entry 10 the coupling of C6F13I provided 81% yield.
But a repetition of this experiment with the bromide instead of the iodide provided less than 1% yield, see Comparative Example herein.
There was a need for a homogenously catalyzed method for the preparation of fluoro alkylated compounds such as ketones by alpha C—H fluoro alkylation, which provides satisfactory yields but does not need Pd catalysis. The method should not be restricted to iodides as alkylating agents only, but should also work with bromides.
Unexpectedly a method for fluoroalkylation of enamines with fluoro alkyl halides was found that surprisingly doesn't even need any metal catalysis. Enamines are easily accessible by the known reaction of a keton with a secondary amine on one hand, on the other hand enamines represent a huge variety of substrates which, when fluoro alkylated, can be used for many purposes and provide an excellent source of intermediates suitable for the use in the areas of pharmaceuticals, agro chemicals and material sciences.
In this text, the following meanings are used, if not otherwise stated:
alkyl linear or branched alkyl, preferably linear
eq, equiv equivalent
“linear” and “n-” are used synonymously with respect to the respective isomers of alkanes
“wt %”, “% by weight” and “weight-%” are used synonymously and mean percent by weight
X2-R3-X1 (FAHALIDE)
Preferably,
Preferably,
Preferably,
In one embodiment, said alkylene, that is represented by R3, wherein in the alkylene chain at least one of the hydrogens is substituted by F, is a perfluoroalkylene.
In one embodiment, said alkyl in the definition of FAHALIDE, wherein in said alkyl at least one of the C atoms is substituted by F, is a perfluoroalkyl.
The term “alkylene” as it is used in instant invention for the definition of R3, with R3 being an alkylene, wherein in the alkylene at least one of the hydrogens is substituted by F, means an alkyl residue which is substituted by X1 and by X2; so FAHALIDE is an alkane substituted by X1 and by X2, wherein at least one of the hydrogens of the alkane is substituted by F.
ENAM may be any enamine formed by a reaction of a secondary amine with a ketone. In the context of the present invention, the definition of “enamine” preferably excludes 2-aminothiazoles, more preferably it excludes thiazoles, even more preferably it excludes the situation where the enamine group is part of an aromatic system, and most preferably it excludes α,β-unsaturated imines (whether part of an aromatic system or otherwise).
Preferably, the fluoroalkylation of said enamine ENAM by a reaction REAC2 occurs at a carbon atom of said ENAM (C-fluoroalkylation). More preferably, the carbon atom at which the C-fluoroalkylation occurs is a carbon atom directly adjacent to the carbonyl group of the ketone (α-carbon) which was reacted with a secondary amine to obtain the enamine ENAM.
ENAM may be a compound of formula (ENAM);
wherein
the N atom depicted with (i) is a tertiary, non-aromatic N atom;
the C atoms depicted with (ii) and (iii) are non-aromatic C atoms.
ENAM may be a compound of formula (ENAM-I);
wherein
the N atom depicted with (i) is a tertiary, non-aromatic N atom;
the C atoms depicted with (ii) and (iii) are non-aromatic C atoms;
R20 and R21 are identical or different and selected from the group consisting of H, C1-10 alkyl, C(O)—C1-4 alkyl, COOH, C(O)—O—C1-4 alkyl;
or
R20 and R21 form together with the 3 C atoms in —C(ii)H=C(i)(N(iii)(R10)R11)-CH2—, which connect R20 and R21 and with (i), (ii) and (iii) as defined herein, a 5, 6 or 7 membered carbocyclic or heterocyclic, non-aromatic ring RINGA;
the 5 membered RINGA being a ring RINGA-V as depicted in formula (RINGA-V),
the 6 membered RINGA being a ring RINGA-VI as depicted in formula (RINGA-VI), and
the 7 membered RINGA being a ring RINGA-VII as depicted in formula (RINGA-VII);
wherein
each of the two endocyclic C atoms depicted with (1) and (2) in case of RINGA-V,
each of the three endocyclic C atoms depicted with (1), (2) and (3) in case of RINGA-VI, and
each of the four endocyclic C atoms depicted with (1), (2), (3) and (4) in case of RINGA-VII
wherein
each of the two endocyclic C atoms depicted with (1) and (2) in case of RINGB-V,
each of the three endocyclic C atoms depicted with (1), (2) and (3) in case of RINGB-VI, and
each of the four endocyclic C atoms depicted with (1), (2), (3) and (4) in case of RINGB-VII
The N atom depicted with (i) in ENAM-I is the same N atom as depicted with (i) in ENAM, and
the C atoms depicted with (ii) and (iii) in ENAM-I are the same C atoms as depicted with (ii) and (iii) in ENAM.
When R20 and R21 together with the 3 C atoms in the —C(ii)H=C(i)(N(iii)(R10)R11)-CH2— of formula (ENAM-I), which connect R20 and R21 and with (i), (ii) and (iii) as defined herein, are part of a steroid ring system, said steroid ring system may have gonane as steroid nucleus with a carbonyl (oxo substituent) at C-3. Ring A in the steroid ring system with gonane as steroid nucleus and with a carbonyl (oxo substituent) at C-3 may be saturated.
ENAM-I is formed by a reaction of a secondary amine with this carbonyl at C-3.
The steroid ring system with a carbonyl (oxo substituent) at C-3 may be cholesterone, dihydrocholesterone, dihydrotestosterone, dihydroprogesterone, dihydrocortisol, dihydrocortisone, dihydronorethisterone, dihydroaldosterone, dihydrocorticosterone, dihydroandrostenedione and the like.
Preferably, R20 and R21 are identical or different and selected from the group consisting of H, C1-4 alkyl, C(O)—C1-2 alkyl, COOH, C(O)—O—C1-2 alkyl;
or
Embodiments of ENAM are
The reaction product of REAC2 is a fluoroalkylated ENAM.
The molar amount of FAHALIDE in REAC2 may be from 0.01 to 10 fold, more preferably from 0.05 to 5 fold, even more preferably from 0.1 to 4 fold, especially from 0.1 to 3 fold, more especially from 0.2 to 2.1 fold, of the molar amount of ENAM.
The molar amount of BAS in REAC2 may be from 0.1 to 10 fold, preferably from 0.2 to 5 fold, even more preferably from 0.3 to 4 fold, especially from 0.4 to 3.1 fold, of the molar amount of ENAM.
REAC2 may be done in a solvent SOLV2, SOLV2 may be THF, Et2O, toluene, Heptane, acetonitrile, DCM or ethyl acetate;
preferably, REAC2 may be done in a solvent SOLV2, SOLV2 may be THF, Et2O, toluene, Heptane, acetonitrile or DCM.
The amount of SOLV2 in REAC2 may be from 2 to 100 fold, preferably from 3 to 50 fold, even more preferably from 3 to 25 fold, especially from 3 to 15 fold, of the weight of ENAM.
The reaction temperature TEMP2 of REAC2 may be from −10 to 150° C., preferably, from −5 to 120° C., more preferably from 0 to 100° C., even more preferably from 10 to 90° C.
The reaction time TIME2 of REAC2 may be from 1 to 100 h, preferably, from 2 to 100 h, more preferably from 5 to 100 h, even more preferably from 10 to 100 h.
REAC2 may be done under ambient pressure or under elevated pressure; the pressure of REAC2 may result from or be determined by the combination of the chosen TEMP2 together with the vapor pressure of the reaction mixture.
REAC2 may be done under inert atmosphere, the inert atmosphere may be provided by nitrogen or argon.
REAC2 is preferably done in the absence of water or at least with a minimized amount of water present. In order to minimize the amount of water present in REAC2 various measures can be taken such as drying of any of the substances prior to REAC2, which are present in REAC2, such as substrate, FAHALIDE, BAS or any solvent; or
Preferably, a molecular sieve has a pore size of from 2 to 6 angstrom.
A molecular sieve may be a sodium aluminum silicate, such as Na12[(AlO2)12(SiO2)12] xH2O.
ENAM may be prepared with a reaction REAC1 of a secondary amine SEKAM with a ketone KET.
SEKAM may be any secondary amine which is capable for forming an enamine with a ketone.
SEKAM may be a compound of formula (SEKAM);
wherein
the N atom depicted with (i) is a secondary, non-aromatic N atom.
SEKAM may be a compound of formula (SEKAM-I);
wherein
the N atom depicted with (i) is a secondary, non-aromatic N atom;
R10 and R11 are as defined herein, also with all their embodiments.
Embodiments of SEKAM are pyrrolidine, morpholine, piperidine, hexamethyldisilazane, diisopropylamine and diethylamine;
preferably, pyrrolidine and morpholine.
KET may be any ketone which is capable for forming an enamine with a secondary amine.
KET may be a compound of formula (KET);
wherein
the C atoms depicted with (ii) and (iii) are non-aromatic C atoms.
KET may be a compound of formula (KET-I);
wherein
the C atoms depicted with (ii) and (iii) are non-aromatic C atoms;
R20 and R21 are as defined herein, also with all their embodiments.
Embodiments of KET are
The molar amount of SEKAM in REAC1 may be from 1 to 10 fold, preferably from 1 to 5 fold, more preferably from 1 to 4 fold, even more preferably from 1 to 3 fold, especially from 1 to 2.3 fold, of the molar amount of KET.
REAC1 may be done in a solvent SOLV1, SOLV1 may be THF, Et2O, toluene, Heptane, acetonitrile, DCM or ethyl acetate;
preferably, REAC1 may be done in a solvent SOLV1, SOLV1 may be THF, Et2O, toluene, Heptane, acetonitrile or DCM.
The amount of SOLV1 in REAC1 may be from 2 to 100 fold, preferably from 3 to 50 fold, even more preferably from 3 to 25 fold, especially from 3 to 15 fold, of the weight of KET.
The reaction temperature TEMP1 of REAC1 may be from −10 to 150° C., preferably, from −5 to 120° C., more preferably from 0 to 100° C., even more preferably from 10 to 90° C.
The reaction time TIME1 of REAC1 may be from 1 to 100 h, preferably, from 2 to 100 h, more preferably from 5 to 100 h, even more preferably from 10 to 100 h.
REAC1 may be done under ambient pressure or under elevated pressure; the pressure of REAC1 may result from or be determined by the combination of the chosen TEMP1 together with the vapor pressure of the reaction mixture.
REAC1 may be done under inert atmosphere, the inert atmosphere may be provided by nitrogen or argon.
SOLV1 and SOLV2 may be the same.
For TIME1 and TIME2 the same time may be chosen.
For TEMP1 and TEMP2 the same temperature may be chosen.
Preferably, REAC1 and REAC2 are done without intermediate isolation of ENAM.
Preferably, REAC1 and REAC2 are done in the same reaction vessel.
After REAC2, the fluoralkylated ENAM may be hydrolyzed with water in a reaction REAC3 to provide SEKAM and a flouralkylated KET.
REAC3 is preferably done under acidic conditions;
said acidic condition may be provided for by the presence of an acid during REAC3;
Said acid may be used in form of an aqueous solution.
The molar amount of water in REAC3 may be the same as or greater than the molar amount of ENAM.
The molar amount of said acid in REAC3 may be a catalytic amount with respect to the molar amount of the fluoroalkylated ENAM, or may be the same as or greater than the molar amount of ENAM. For example, 1 N aqueous HCl may be used.
REAC3 is done by mixing the fluoroalkylated ENAM with water and optionally with said acid. Said mixing is preferably done after REAC2.
REAC3 may be done in a solvent SOLV3, SOLV3 may be THF, Et2O, toluene, Heptane, acetonitrile, DCM or ethyl acetate;
preferably, REAC3 may be done in a solvent SOLV3, SOLV3 may be THF, Et2O, toluene, Heptane, acetonitrile or DCM.
The amount of SOLV3 in REAC3 may be from 2 to 100 fold, preferably from 3 to 50 fold, even more preferably from 3 to 25 fold, especially from 3 to 15 fold, of the weight of fluoroalkylated ENAM.
The reaction temperature TEMP3 of REAC3 may be from −10 to 150° C., preferably, from −5 to 120° C., more preferably from 0 to 100° C., even more preferably from 10 to 90° C.
The reaction time TIME3 of REAC3 may be from 15 min to 24 h, preferably, from 30 min to 12 h, more preferably from 30 min to 6 h, even more preferably from 30 min to 3 h.
REAC3 may be done under ambient pressure or under elevated pressure; the pressure of REAC3 may result from or be determined by the combination of the chosen TEMP3 together with the vapor pressure of the reaction mixture.
REAC3 may be done under inert atmosphere, the inert atmosphere may be provided by nitrogen or argon.
SOLV2 and SOLV3 may be the same.
Preferably, REAC2 and REAC3 are done without intermediate isolation of the fluoroalkylated ENAM after REAC2.
When REAC2 and REAC3 are done without intermediate isolation of the fluoroalkylated ENAM after REAC2, then the reaction mixture obtained after REAC2 may be mixed with water and optionally with said acid.
Preferably, REAC2 and REAC3 are done in the same reaction vessel.
Preferably, REAC1, REAC2 and REAC3 are done without intermediate isolation of ENAM or of the fluoroalkylated ENAM.
Preferably, REAC1, REAC2 and REAC3 are done in the same reaction vessel.
When REAC1 and REAC2 are done without intermediate isolation of ENAM, then DRYAG may be present in the reactions REAC1 and REAC2.
ENAM after REAC1, the fluoroalkylated ENAM after REAC2 and the fluoroalkylated KET after REAC3 may be isolated according to procedures known to the skilled person.
A mixture of the substrate, FAHALIDE, BAS and the solvent (all equivalents and amounts are specified in the respective tables) were placed in a thick-walled pressure tube (Ace pressure tube, Sigma-Aldrich Art. No Z564559). The gas atmosphere in the pressure tube was flushed with argon, the tube was closed with a screw cap and heated (reaction temperature and reaction time are specified in the respective table). The resulting mixture was cooled to room temperature. Solids were removed by centrifugation (3000 rpm, 15 min). The obtained product solution was analyzed by quantitative GC analysis (internal standard hexadecane), 19F-NMR analysis using the internal standards 1,2-difluorobenzene, 1,4-difluorobenzene or benzotrifluoride, or GC-MS.
A mixture of the substrate, FAHALIDE, SEKAM, BAS, DRYAG and the solvent (all equivalents and amounts are specified in the respective table) were placed in a thick-walled pressure tube (Ace pressure tube, Sigma-Aldrich Art. No Z56455964575). The gas atmosphere in the pressure tube was flushed with argon, the tube was closed with a screw cap and heated (reaction temperature and reaction time are specified in the respective tables). The resulting reaction mixture was mixed with 1 N aqueous hydrochloric acid (2 eq) for 1 hour at ambient temperature. The organic phase was then separated and the product was purified by pipette column chromatography using FluoroFlash® reverse phase silica gel (Sigma Aldrich No.: 00866) and a gradient solvent elution (1. MeOH:H2O (4:1, 10 mL) 2. MeOH (100%, 10 mL) 3. acetone (100%, 10 mL) for long chains fluoroalkyl chains (alkyl chain containing 10 or more carbon atoms) or by normal phase silical gel chromatography using silicagel (Sigma Aldrich No.: 236802) and a gradient solvent elution (1. Pentane Ether (100%) 2. Pentane: Diethylether (50%: 50%, 10 ml) for fluoroalkyl chains containing less than 10 carbon atoms.
The obtained product solution was analyzed by quantitative GC analysis (internal standard hexadecane), 19F-NMR analysis using the internal standards 1,2-difluorobenzene, 1,4-difluorobenzene or benzotrifluoride, or GC-MS.
A mixture of the substrate, FAHALIDE, SEKAM, BAS, DRYAG and solvent (all equivalents and amounts are specified in the respective tables) were placed in a thick-walled pressure tube (Ace pressure tube, Sigma-Aldrich Art. No. Z564559). The gas atmosphere in the pressure tube was flushed with argon, the tube was closed with a screw cap and heated (reaction temperature and reaction time are specified in the respective tables). The resulting mixture was cooled to room temperature. Solids were removed by centrifugation (3000 rpm, 15 min). The obtained product solution was analyzed by quantitative GC analysis (internal standard hexadecane), 19F-NMR analysis using the internal standards 1,2-difluorobenzene, 1,4-difluorobenzene or benzotrifluoride, or GC-MS.
A mixture of the substrate, FAHALIDE, BAS and solvent (all equivalents and amounts are specified in the respective tables) were placed in a thick-walled pressure tube (Ace pressure tube, Sigma-Aldrich Art. No. Z564559). The gas atmosphere in the pressure tube was flushed with argon, the tube was closed with a screw cap and heated (reaction temperature and reaction time are specified in the respective table). The resulting mixture was cooled to room temperature and mixed with 1 N aqueous hydrochloric acid for 1 hour. The organic phase was then separated and analyzed by quantitative GC analysis (internal standard hexadecane), 19F-NMR analysis using the internal standards 1,2-difluorobenzene, 1,4-difluorobenzene or benzotrifluoride, or GC-MS.
Details of the examples are given in Tables 1, 2 and 3.
Examples 1 to 28 were done according to Protocol 1—REAC2.
Examples 29 to 72 and 81 were done according to Protocol 2—REAC1, REAC2 and REAC3.
Examples 77 to 80 were done according to Protocol 3—REAC1 and REAC2.
Examples 73 to 76 were done according to Protocol 4—REAC2 and REAC3.
The (a) in Examples 63 and 64 denote where the side chain is bonded to the ring with the indicated stereochemistry.
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph) additional 16% yield of
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph): 62% yield
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph): 80% yield
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph): 70% yield
19F-NMR (CF3Ph): 40% yield
19F-NMR (CF3Ph): 75% yield
19F-NMR (CF3Ph): 80% yield
19F-NMR (CF3Ph): 79% yield
19F-NMR (CF3Ph): 76% yield
19F-NMR (CF3Ph): 73% yield
19F-NMR (CF3Ph): 85% yield
19F-NMR (CF3Ph): 76% yield
19F-NMR (CF3Ph): 79% yield
19F-NMR (CF3Ph): 52% yield
19F-NMR (CF3Ph): 67% yield
19F-NMR (CF3Ph): 88% yield
19F-NMR (CF3Ph): 85% yield
19F-NMR (CF3Ph): 67% yield
19F-NMR (CF3Ph): 84% yield
19F-NMR (CF3Ph): 81% yield
19F-NMR (CF3Ph): 82% yield
19F-NMR (CF3Ph): 57% yield
19F-NMR (CF3Ph): 55% yield
19F-NMR (CF3Ph) Usage of CDCh with some humidity Additional yield of 15% of
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph)
19F-NMR (CF3Ph): 38% yield
| Number | Date | Country | Kind |
|---|---|---|---|
| 19179702.6 | Jun 2019 | EP | regional |
| 19184587.4 | Jul 2019 | EP | regional |
| 19186599.7 | Jul 2019 | EP | regional |
The present application is the national stage entry of International Patent Application No. PCT/EP2020/066351 having a filing date of Jun. 12, 2020, which claims priority to U.S. Provisional Patent Application No. 62/860,393 having a filing date of Jun. 12, 2019, European Patent Application No. 19 179 702.6 having a filing date of Jun. 12, 2019, European Patent Application No. 19 184 587.4 having a filing date of Jul. 5, 2019, and European Patent Application No. 19 186 599.7 having a filing date of Jul. 16, 2019, which are incorporated herein by reference. The invention discloses a method for fluoroalkylation of enamines with a fluoro alkyl halide in the presence of a base.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/066351 | 6/12/2020 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62860393 | Jun 2019 | US |
