Trans-isomeric heterocyclic compounds and process for preparing same
阅读说明：本技术 反式异构杂环化合物及其制备方法 (Trans-isomeric heterocyclic compounds and process for preparing same ) 是由 许明珠 林助强 严启峰 许涵霈 陈文章 邹先岩 于 2018-08-10 设计创作，主要内容包括：一种如通式(I)的反式异构化合物或其药学上可接受的盐：<Image he="360" wi="700" file="DDA0002227266430000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>其中,R<Sub>1</Sub>为C<Sub>1</Sub>-C<Sub>5</Sub>烷基或C<Sub>3</Sub>-C<Sub>5</Sub>环烷基,且反式异构化合物的反式：顺式比为至少70:30。并进一步提供制备反式异构化合物的方法。(A trans-isomeric compound of the general formula (I): Wherein R is 1 Is C 1 ‑C 5 Alkyl or C 3 ‑C 5 cycloalkyl, and trans of the trans isomeric compounds: the cis ratio is at least 70: 30. And further provides a process for preparing trans-isomeric compounds.)
1. A trans-isomeric compound of formula (I) or a pharmaceutically acceptable salt thereof,
Wherein R is1Is C1-C5Alkyl or C3-C5Cycloalkyl radicals, and the reactiontrans in a mixture of isomeric compounds of formula (la): the cis ratio is at least 70: 30.
2. The trans-isomeric compound, or a pharmaceutically acceptable salt thereof, according to claim 1, wherein R1Is C1-C5An alkyl group.
3. the trans-isomeric compound, or a pharmaceutically acceptable salt thereof, according to claim 1, wherein R1Is methyl.
4. the trans-isomeric compound, or a pharmaceutically acceptable salt thereof, according to claim 1, in the (3S,5S) -configuration of formula (Ia):
5. The trans-isomeric compound, or a pharmaceutically acceptable salt thereof, according to claim 1, in the (3R,5R) -configuration of formula (Ib):
6. a process for the preparation of trans-isomeric compounds of formula (I) or a pharmaceutically acceptable salt thereof,
The process comprises hydrogenating a compound of formula (II) or a pharmaceutically acceptable salt thereof in the presence of an inert solvent using a palladium catalyst to obtain the trans form: trans isomeric compounds of general formula (I) having a cis ratio of at least 70:30 or a pharmaceutically acceptable salt thereof,
Wherein R in the general formulae (I) and (II)1is C1-C5Alkyl or C3-C5A cycloalkyl group.
7. The method of claim 6, further comprising the step of optically resolving the trans-isomeric compound or a pharmaceutically acceptable salt thereof using an acidic resolving agent to obtain an enantiomer of the trans-isomeric compound or a pharmaceutically acceptable salt thereof, wherein the enantiomer may be in the (3S,5S) -configuration of formula (Ia) or in the form of the (3R,5R) -configuration of formula (Ib):
8. The method of claim 6, wherein R1Is C1-C5An alkyl group.
9. The method of claim 8, wherein R1Is methyl.
10. The method of claim 6, wherein the palladium catalyst is Pd (OH)2/C、Pd/C、Pd(OAc)2、Pd/Al2O3Or a combination thereof, and the palladium content in the palladium catalyst is 0.01 wt% to 30 wt%.
11. The method of claim 10, further comprising an additional transition metal catalyst.
12. The method of claim 11, wherein the additional transition metal catalyst is Pt/C or Rh/C.
13. The method of claim 6, wherein the inert solvent is water, C1-C10An ester,C3-C10Cycloalkanes, Tetrahydrofuran (THF), Dimethylformamide (DMF), acetonitrile, C1-C10An alcohol, an alkylene glycol monoalkyl ether carboxylate, an amide solvent, an organic acid, or a combination thereof.
14. The process of claim 13 wherein the inert solvent is combined with one or more mineral acids.
15. The method of claim 6, wherein the inert solvent is water, C1-C10Esters, C3-C10Cycloalkanes, THF, DMF, C1-C10Alcohol, propylene glycol methyl ether acetate, N-dimethylacetamide, C1-C5Carboxylic acid, C1-C5A sulfonic acid, or a combination thereof.
16. the method of claim 15, wherein the inert solvent is water, methanol, ethanol, isopropanol, formic acid, acetic acid, ethyl acetate, methanesulfonic acid, or a combination thereof.
17. The process of claim 16 wherein the inert solvent is combined with hydrochloric acid.
18. The method of claim 6, wherein the inert solvent is an organic acid or a combination of an organic acid and one or more solvents selected from the group consisting of: water, C1-C10Esters, C3-C10Cycloalkane, THF, DMF, acetonitrile, alkylene glycol monoalkyl ether carboxylate, amide solvent, C1-C10Alcohols, and inorganic acids.
19. The method of claim 18, wherein the organic acid is formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, or a combination thereof.
20. The process of claim 7, wherein the acidic resolving agent is deoxycholic acid, (-)2,3,4, 6-diisopropylidene-2-one-L-gulonic acid monohydrate, D- (-) -quinic acid, L-pyroglutamic acid, (-) -monomethyl succinate, N-acetyl-D- (+) -leucine, N-acetyl-L-methionine, (R) - (+) -N- (1-phenylethyl) succinamic acid, (S) - (+) -5-oxo-2-tetrahydrofuranic acid, (R) - (+) -N- (1-phenylethyl) o-carbamoylbenzoic acid, (-) -mono- (1R) -menthyl phthalate, menthyl succinate, or, (-) -menthoxyacetic acid, (S) - (+) -mandelic acid, L- (+) -tartaric acid, D- (+) -camphoric acid, (-) -dibenzoyl-L-tartaric acid anhydride, (-) -dibenzoyl-L-tartaric acid monohydrate, (-) -O, O '-dibenzoyl-L-tartaric acid mono (dimethylamide), D- (+) -10-camphorsulfonic acid, L- (+) -lactic acid, L- (-) -malic acid, (-) -O, O' -di-p-toluoyl-L-tartaric acid, (R) - (-) -naproxen, (S) -ibuprofen, or R-form or S-form thereof.
21. The method of claim 7, further comprising the step of recrystallizing the enantiomer of (3S,5S) -configuration or the enantiomer of (3R,5R) -configuration using a recrystallization solvent.
22. the method of claim 21, wherein the recrystallization solvent is water, C1-C10Esters, C3-C10Cycloalkanes, THF, DMF, acetonitrile, C1-C10An alcohol, or a combination thereof.
23. a trans-isomeric compound of general formula (I), or a pharmaceutically acceptable salt thereof, prepared using the process of any one of claims 6 to 22:
Wherein, the trans-isomer compound is trans: the cis ratio is at least 70: 30.
Technical Field
The present invention relates to trans-isomeric heterocyclic compounds, i.e., piperidines, and methods for preparing these stereospecific isomers.
Background
Some heterocyclic compounds, such as piperidine, have pharmaceutical activity. Their pharmaceutical activity and safety are reported to vary depending on the stereochemical configuration of the substituent on the piperidine ring. See, for example, Pharmacia (Pharmacia),1989,25(4), 311-. Therefore, efficient synthesis of piperidines with high stereoselectivity is very important.
Methods for preparing cis/trans mixtures of piperidines, such as piperidine-3-carboxamide, are known in the art. See, e.g., DeNinno et al, Bioorganic chemistry and medicine communications (Bioorganic and Medicinal Letters), 2011,21, 3095-; and Gancia et al, WO 2015/091584. However, the known processes produce predominantly the non-stereoselective isomers or predominantly the cis isomers. It is therefore desirable to develop a new process for the preparation of the piperidine trans isomer.
Summary of The Invention
One aspect of the present specification is a process for preparing a trans-isomeric compound of formula (I) or a pharmaceutically acceptable salt thereof,
The process of the present invention produces the trans isomer of piperidine in unexpectedly high yields and high stereoselectivities, comprising: a step of hydrogenating the compound of the general formula (II) or a pharmaceutically acceptable salt thereof using a palladium catalyst in the presence of an inert solvent,
To obtain the trans: a trans-isomeric compound of formula (I) having a cis ratio of at least 70:30 (up to 99.9: 0.1) or a pharmaceutically acceptable salt thereof, wherein R in formulae (I) and (II)1Is C1-C5Alkyl or C3-C5A cycloalkyl group.
The above method may further comprise a step of resolution reaction by optically resolving the trans-isomeric compound of general formula (I) using an acidic resolving agent. The process provides optically enriched enantiomers of trans isomeric compounds of general formula (I) or a pharmaceutically acceptable salt thereof. The acidic resolving agent may be in the R-form (R-form) or in the S-form (S-form). The obtained enantiomer may be recrystallized using a recrystallization solvent, if necessary.
Another aspect of the present specification is a trans-isomeric compound of formula (I):
Wherein R is1Is C1-C5Alkyl or C3-C5Cycloalkyl, and trans of the trans isomeric compounds: the cis ratio is at least 70: 30. In one embodiment, R1Can be C1-C5Alkyl groups, such as methyl.
The trans-isomeric compounds of formula (I) may be in the (3S,5S) -configuration, i.e. formula (Ia) as shown below, or in the (3R,5R) -configuration, i.e. formula (Ib) as shown below:
The term "C" in the present invention1-C5Alkyl "refers to a straight or branched chain hydrocarbon group containing 1 to 5 carbon atoms. C1-C5Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, and isopropyl. The term "C3-C5Cycloalkyl "refers to a saturated cyclic hydrocarbon moiety containing from 3 to 5 carbon atoms. C3-C5Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, and cyclopentyl. Unless otherwise indicated, references herein to alkyl and cycloalkyl include both substituted and unsubstituted moieties. Possible substituents on alkyl and cycloalkyl groups include, but are not limited to, amino, hydroxyl, halogen, thio, amido, aminoacyl, aminothioacyl, amidino, guanidino, ureido, cyano, nitro, nitroso, azido, acyl, thioacyl, acyloxy, carboxyl, and carboxylate.
In another aspect of the present specification, there is disclosed a trans-isomeric compound of formula (I) prepared according to the above process.
The present invention is described in detail below. Other features and objects of the present invention will become apparent from the following detailed description of several embodiments and the appended claims.
Detailed Description
Firstly, the invention discloses a trans-isomeric compound with a general formula (I) or a pharmaceutically acceptable salt thereof:
In the general formula, R1Is C1-C5Alkyl or C3-C5A cycloalkyl group. In some embodiments, R1Is C1-C5Alkyl groups such as methyl, ethyl or isopropyl. In some embodiments, the trans isomeric compound is trans: a cis ratio of at least 70:30, e.g. 80: 20. 90:10 or 99: 1.
the trans isomeric compounds may exist as pure enantiomers. Exemplary enantiomers are as shown in the summary above for a compound of formula (Ia) in the (3S,5S) -configuration or a pharmaceutically acceptable salt thereof, or a compound of formula (Ib) in the (3R,5R) -configuration or a pharmaceutically acceptable salt thereof.
The term "pharmaceutically acceptable salt" refers to acid or base salts of the compounds of the present invention. Pharmaceutically acceptable salts in some embodiments include acid addition salts that can be formed by reacting a compound with a pharmaceutically acceptable acid, such as hydrochloric acid, hydrobromic acid, hydrofluoric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, maleic acid, lactic acid, malic acid, tartaric acid, citric acid, picric acid, methanesulfonic acid, benzenesulfonic acid, aspartic acid, and glutamic acid.
The above compounds include the compounds themselves, and if applicable, salts, prodrugs, polymorphs, stereoisomers and solvates thereof. For example, a salt may be formed from an anion and a positively charged group (e.g., amino group) on a compound of one of the above formulae. Suitable anions include chloride, bromide, iodide, sulfate, nitrate, phosphate, citrate, methylsulfonate, trifluoroacetate, acetate, malate, tosylate, tartrate, fumarate, glutamate, glucuronate, lactate, glutarate and maleate. Similarly, salts can also be formed from cations and negatively charged groups (e.g., carboxylate ions) on compounds of one of the above formulas. Suitable cations include sodium, potassium, magnesium, calcium, and ammonium ions, such as tetramethylammonium. Compounds of the above formula also include those salts containing quaternary nitrogen atoms. For simplicity of calculation, reference to the weight of a compound in this specification refers to the weight of the free base form of the compound, unless otherwise indicated. Examples of prodrugs include esters and other pharmaceutically acceptable derivatives, which, when administered to a subject, are capable of providing the active compound. Solvates refer to the complexes of the active compound with pharmaceutically acceptable solvents. Examples of pharmaceutically acceptable solvents include water, ethanol, isopropanol, ethyl acetate, acetic acid, and ethanolamine.
Methods of preparing trans-isomeric compounds of formula (I) or pharmaceutically acceptable salts thereof are also within the scope of the present invention.
The process comprises hydrogenating a compound of the general formula (II) disclosed in the preceding summary in the presence of an inert solvent using a palladium catalyst to stereoselectively produce the trans form: a trans isomeric compound of formula (I) having a cis ratio of at least 70:30 or a pharmaceutically acceptable salt thereof.
Further, the stereoselective hydrogenation of the compound of formula (II) is carried out in the presence of a palladium catalyst and under suitable pressure using various solvents. It is trans: the cis ratio is determined by Nuclear Magnetic Resonance (NMR) spectroscopy.
The palladium catalyst may comprise one or more palladium compounds, e.g. Pd (OH)2Pd/C (palladium on carbon), Pd (OAc)2(Palladium acetate), Pd/Al2O3(palladium alumina), or a combination thereof. In another aspect, the palladium catalyst may optionally further comprise another transition metal catalyst, including Pt/C and Rh/C. The palladium content of the palladium catalyst may be from about 0.01 weight percent (wt%) to about 30 wt%, or from about 0.1 wt% to about 25 wt%, or from about 1 wt% to about 20 wt%, or from about 2 wt% to about 20 wt%, or from about 5 wt% to about 20 wt%.
Examples of inert solvents include, but are not limited to, water, C1-C10Esters (e.g. ethyl acetate and methyl acetate), C3-C10Cycloalkanes (e.g. cyclopropane, cyclobutane, cyclopentane and cyclohexane), Tetrahydrofuran (THF), Dimethylformamide (DMF), acetonitrile, C1-C10Alcohols (e.g., methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, ethylene glycol, propylene glycol and butylene glycol), alkylene glycol monoalkyl ethers (e.g., propylene glycol methyl ether, propylene glycol ethyl ether and propylene glycol propyl ether), alkylene glycol monoalkyl ether carboxylates (e.g., propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate and propylene glycol propyl ether ethylene glycol acetate)Acid esters), amide solvents (e.g., N-dimethylacetamide and N, N-dimethylformamide), organic acids (e.g., C)1-C10Carboxylic acid and C1-C10Sulfonic acid), or a combination thereof. In one embodiment, the inert solvent may comprise two or more C' s1-C10Esters, or two or more kinds of C3-C10Cycloalkanes, and the like. In another embodiment, the inert solvent may also optionally comprise one or more inorganic acids (e.g., hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid).
In one embodiment, the inert solvent may be water, C1-C5Esters, C3-C6Cycloalkanes, THF, DMF, acetonitrile, C1-C5Alcohols, alkylene glycol monoalkyl ethers, alkylene glycol monoalkyl ether carboxylates, N-dimethylacetamide, C1-C5Carboxylic acids (e.g., formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, difluoroacetic acid, trifluoroacetic acid, and combinations thereof), C1-C5A sulfonic acid (e.g., methanesulfonic acid), or a combination thereof, and may optionally include one or more mineral acids of hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid. In another embodiment, the inert solvent may be water, C1-C5Esters, C3-C6Cycloalkanes, THF, DMF, C1-C5Alcohol, propylene glycol methyl ether acetate, N-dimethylacetamide, C1-C5carboxylic acid, C1-C5A sulfonic acid, or a combination thereof, and may optionally comprise hydrochloric acid. In another embodiment, the inert solvent may be water, methanol (MeOH), ethanol (EtOH), isopropanol (i-PrOH), ethyl acetate, formic acid, acetic acid, methanesulfonic acid, or a combination thereof, and may optionally include hydrochloric acid.
Surprisingly, inert solvents containing inorganic acids (e.g., hydrochloric, sulfuric, phosphoric and nitric acids) are capable of providing very high stereoselectivity for the trans-isomerization of piperidine. By way of example, the inert solvent may be an organic acid or an organic acid and one or more solvents, such as water, C1-C10Esters, C3-C10Cycloalkanes, THF, DMF, acetonitrile, C1-C10Alcohols, alkylene glycol monoalkyl, alkylene glycolsA combination of a monoalkylether carboxylate, an amide solvent, and an inorganic acid. In one embodiment, the inert solvent may be C1-C5Carboxylic acid, C1-C5Sulfonic acid or a combination thereof, optionally with one or more of water, C1-C10Esters, C3-C10Cycloalkanes, THF, DMF, acetonitrile, C1-C10An alcohol, an alkylene glycol monoalkyl ether carboxylate, an amide solvent and a solvent for an inorganic acid are used in combination. In another embodiment, the inert solvent may be formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, or combinations thereof, optionally with one or more of water, C1-C10esters, C3-C10Cycloalkanes, THF, DMF, acetonitrile, C1-C10alcohol, alkylene glycol monoalkyl ether carboxylate, amide solvent, C1-C10A sulfonic acid and an inorganic acid solvent are used in combination.
Also unexpectedly, containing an organic acid (e.g., C)1-C5Carboxylic acid and C1-C5sulfonic acid) can provide extremely high stereoselectivity for the trans-isomerization of piperidine. As an example, the inert solvent may be C1-C5Esters, C3-C6Cycloalkanes, THF, DMF, acetonitrile, C1-C5alcohol, propylene glycol methyl ether acetate, N-dimethylacetamide, C1-C5Carboxylic acid, C1-C5Sulfonic acids and combinations thereof, and optionally in combination with water.
In one embodiment, the hydrogenation reaction may be carried out at 10-100 deg.C, such as 15-80 deg.C, 20-70 deg.C, 20-60 deg.C, 20-50 deg.C, and 25-45 deg.C. As an example, the hydrogenation reaction can be carried out at 25 ℃,30 ℃, 35 ℃, 40 ℃,45 ℃,50 ℃,55 ℃ or 60 ℃.
The hydrogenation reaction may be carried out under a hydrogen pressure of 1-60 bar (bar), 5-50 bar, 10-40 bar, 15-30 bar or 15-25 bar.
The reaction time for the hydrogenation can be adjusted within the range of 1 to 80 hours, depending on the palladium catalyst, the hydrogen pressure, the reaction temperature and the hydrogenation apparatus used. Completion of the hydrogenation reaction was confirmed by NMR. After the hydrogenation reaction is completed, purification may be performed by filtration, concentration under reduced pressure, and distillation steps. In one embodiment, the trans isomeric piperidine obtained may be converted to the salt form, if desired. In an exemplary process, the hydrogenation reaction is carried out at 25-45 ℃ and a hydrogen pressure of 15-25 bar.
By using the preparation process of the present invention, trans: the cis ratio is 70:30 to 99.9:0.1 (e.g., 70:30 to 99:1, 70:30 to 95:5, 70:30 to 90:10, 75:25 to 99.9:0.1, 75:25 to 95:5, 75:25 to 90:10, 80:20 to 99.9:0.1, 80:20 to 99:1, 80:20 to 95:5, 80:20 to 90:10, 85:15 to 99.9:0.1, 85:15 to 99:1, 85:15 to 95:5, and 85:15 to 90: 10).
The above preparation method may further comprise a resolution step of optically resolving the trans-isomeric piperidine by using an acidic resolving agent. This procedure provides an optically enriched enantiomer of the trans-isomer compound of formula (I) or a pharmaceutically acceptable salt thereof, i.e., an enantiomer in the (3S,5S) -or (3R,5R) -configuration, in high yield and purity. Wherein the acidic resolving agent may be in the R-form or the S-form. The enantiomer thus obtained may be further recrystallized using a recrystallization solvent.
The term "acidic resolving agent" refers to an acidic compound which can lead to the precipitation of diastereomers which contain the desired enantiomer in high chemical and optical yields.
The following discloses the optical resolution reaction:
Wherein R is1Is C1-C5Alkyl or C3-C5A cycloalkyl group. Optical isomers containing both salt forms of the general formula (1a) having the (3S,5S) -configuration and the general formula (Ib) having the (3R,5R) -configuration can be each obtained by subjecting a trans-isomeric compound of the general formula (I) to optical resolution using an acidic resolving agent.
The enantiomeric excess (i.e., "ee value") of an enantiomer, such as (3S,5S) -configuration (1a) or (3R,5R) -configuration (Ib), can be 70-100%, 80-100%, 90-100%, 95-100%, 99-100%, 70-99.9%, 80-99.9%, 85-99.9%, 90-99.9%, 95-99.9%, or 99-99.9%. The term "ee value" is the difference in the amount of each enantiomer present in the mixture and is relative to the percentage of the total amount of compound in the mixture (× 100%).
The acidic resolving agent may be deoxycholic acid ((-) -2,3:4, 6-di-o-isopropylidene-2-one-L-gulonic acid monohydrate ((-) -2,3:4,6-di-o-isopropylidene-2-keto-L-gulonic acid monohydrate), D- (-) -quinic acid (D- (-) -quinic acid), L-pyroglutamic acid (L-pyroglutamic acid), (-) -succinic acid monomethyl ester ((-) -monomethylsucinate), N-acetyl-D- (+) -leucine (N-acetyl-D- (+) -leucin), N-acetyl-L-methionine (N-acetyl-L-methionine), (R) - (+) -N- (1-phenylethyl) succinamic acid ((R) - (+) -N- (1-phenylethyl) succinamic acid), (S) - (+) -5-oxo-2-tetrahydrofuranic acid ((S) - (+) -5-oxo-2-tetrahydrofuranic acid), (R) - (+) -N- (1-phenylethyl) o-carbamylbenzoic acid ((R) - (+) -N- (1-phenylethyl) phthalamic acid), (-) -mono- (1R) -menthyl phthalate ((-) -mono- (1R) -menthyl phthalate), (-) -menthyloxyacetic acid ((-) -menthyloxyacetic acid), (S) - (+) -mandelic acid ((S) - (+) -mandelic acid), L- (+) -tartaric acid (L- (+) -tartaric acid), D- (+) -camphoric acid (D- (+) -camphoric acid), (-) -dibenzoyl-L-tartaric acid anhydride ((-) -dibenzoyl-L-tartaric acid monohydrate), (-) -dibenzoyl-L-tartaric acid monohydrate, (-) -O, O' -dibenzoyl-L-tartaric acid mono (dimethylamide)), (L- ((-) -L- (+) -benzoic-L-tartaric acid monohydrate), D- (+) -10-camphorsulfonic acid (D- (+) -10-camphorsylfonic acid), L- (+) -lactic acid (L- (+) -lactic acid), L- (-) -malic acid (L- (-) -malic acid), (-) -O, O '-di-p-toluoyl-L-tartaric acid ((-) -O, O' -di-p-toluoyl-L-tartaric acid), (R) - (-) -naproxen ((R) - (-) -naproxen) or (S) -ibuprofen ((S) -ibuprofen).
Acidic resolving agents can be in the R-form and in the S-form, such as (R) - (-) -naproxen and (S) - (+) -naproxen, both of which can be used in the present invention to obtain high enantiomeric excess (ee value).
In one embodiment, the acidic resolving agent is deoxycholic acid (deoxycholic acid), D- (-) -quinic acid (D- (-) -quinic acid), (-) -succinic acid monomethyl ester ((-) -monomethylsucinate), N-acetyl-D- (+) -leucine (N-acetyl-D- (+) -leucine), N-acetyl-L-methionine (N-acetyl-L-methionine), (-) -mono- (1R) -menthyl phthalate ((-) -mono- (1R) -menthyl phthalate), (-) -dibenzoyl-L-tartaric acid anhydride ((-) -dibenzoyl-L-tartaric acid anhydride), (-) -deoxycholic acid anhydride, (-) -deoxycholic L-tartaric acid anhydride, (-) -O, O '-dibenzoyl-L-tartaric acid mono (dimethylamide) (-) -O, O' -dibenzoyl-L-tartaric acid mono (dimethyllamide)), D- (+) -10-camphorsulfonic acid (D- (+) -10-camphorsylfonic acid), L- (+) -lactic acid (L- (+) -lactic acid) or (R) - (-) -naproxen ((R) - (-) -naproxen).
The optical resolution may be carried out in the presence of an inert solvent. The inert solvent used for optical resolution can be water or C1-C10Esters (e.g. ethyl acetate and methyl acetate), C3-C10Cycloalkanes (e.g. cyclohexane), Tetrahydrofuran (THF), Dimethylformamide (DMF), acetonitrile, C1-C10alcohols (e.g., methanol, ethanol, N-propanol, isopropanol, N-butanol, isobutanol), alkylene glycol monoalkyl ethers (e.g., propylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol propyl ether), alkylene glycol monoalkyl ether carboxylates (e.g., propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, and propylene glycol propyl ether acetate), amide solvents (e.g., N-dimethylacetamide and N, N-dimethylformamide), or combinations thereof. In the present invention, the ratio of the inert solvent to the reaction substrate is not particularly limited. For example, the inert solvent may be used in an amount of 0.5 to 100 times the weight of the substrate.
The temperature for optical resolution generally varies depending on the kind of starting material, the resolving agent and the solvent used. The reaction is generally carried out at 20 to 60 ℃ C (e.g., 30 to 50 ℃ C.).
The above optical resolution may further comprise subjecting the compound of (3S,5S) -configuration (Ia) or (3R,5R) -configuration (Ib) to a recrystallization step using a recrystallization solvent to form a product having high optical purity.
The recrystallization solvent may be water, C1-C10esters (e.g. ethyl acetate and methyl acetate), C3-C10Cycloalkanes (e.g. cyclohexane), Tetrahydrofuran (THF), Dimethylformamide (DMF), acetonitrile, C1-C10Alcohols (e.g., methanol, ethanol, N-propanol, isopropanol, N-butanol, isobutanol), alkylene glycol monoalkyl ethers (e.g., propylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol propyl ether), alkylene glycol monoalkyl ether carboxylates (e.g., propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, and propylene glycol propyl ether acetate), amide solvents (e.g., N-dimethylacetamide and N, N-dimethylformamide), or combinations thereof.
In addition, an anti-solvent (anti-solvent) may be used in the recrystallization process. The term "anti-solvent" in the present invention refers to a solvent in which the crystalline compound has limited or poor solubility. Examples of anti-solvents include, but are not limited to, ethyl acetate, acetone, methyl ethyl ketone, toluene, isopropyl acetate (isopropyl acetate), and methyl tert-butyl ether (t-butyl methyl ether).
Without further elaboration, it is believed that one skilled in the art can, based on the description herein, utilize the present invention to its fullest extent. The following examples are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. All publications cited in this specification are herein incorporated in their entirety by reference.
Example 1: stereoselective hydrogenation of 5-methyl-nicotinamide
Watch 1
As shown in the above reaction and table one, 5-methyl-nicotinamide (i.e. compound (III)), different inert solvents and transition metal catalyst were added and reacted in a magnetically stirred autoclave to obtain trans-isomeric compound (IV). Therein, the autoclave was pressurized to 15 bar (bar) with hydrogen and stirred at 45 ℃, and then, the sample in the autoclave was analyzed by NMR.
Table one shows that only trans-forms of 46:54 to 53:47 can be obtained using non-palladium catalysts, i.e. Rh/C or Pt/C: cis ratio (C1 and C2 groups), no significant diastereoisomeric selectivity was observed. Unexpectedly, when a palladium catalyst is used, the hydrogenation of compound (III) favors the stereoselective formation of compound (IV) as the trans isomer, which is trans: the cis ratio was 73:27 to 78:22 (groups E1 to E6). These results indicate that hydrogenation using a palladium catalyst advantageously produces the trans isomeric piperidine.
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