Classifications

• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/62—Carboxylic acid esters
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P41/00—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P41/00—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture
  • C12P41/003—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture by ester formation, lactone formation or the inverse reactions
  • C12P41/005—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture by ester formation, lactone formation or the inverse reactions by esterification of carboxylic acid groups in the enantiomers or the inverse reaction

Definitions

• the invention relates to a method for preparing chiral hydroxy esters, particularly, to a process for preparing chiral hydroxy esters with high optical purities by combining an enzyme and a metal catalyst in a single reaction chamber and inducing multi-step catalytic reactions.
• the kinetic resolution has some advantages - high optical purity of the end product, low unit cost of the enzyme catalyst, and simple reaction condition - and one apparent disadvantage that the yield is less than 50%.
• the asymmetric synthesis leads high optical purity and yield, but causes the increase of production cost due to the use of expensive chiral reagents. Also, the reaction conditions are complicated.
• an enzyme as an enantioselective acylation catalyst is used with a metal catalyst as a racemization catalyst to produce single enantiomer from a racemic mixture.
• the yields of the products by this method are higher than those by optical resolution that uses enzyme catalysts only. Furthermore, this method is cost effective compared to the asymmetric synthesis that uses expensive chiral reagents.
• ketones were successfully transformed to optically pure esters by the combination of an enzyme and a metal catalyst.
• a metal catalyst Jung, H. M.; Koh, J. H.; Kim, M.-J.; Park, J., Org. Lett. 2000, 2, 409; Jung, H. M.; Koh, J. EL; Kim, M.-J.; Park, J., Org. Zett. 2000, 2, 2487.
• an excessive amount of acyl donor is used to increase yields.
• the excessive use of acyl donor increases the production cost and makes the separation of required product difficult because the acyl donor remains unreacted in a large portion and has similar polarity with that of product.
• the invention provides a process for synthesizing chiral hydroxy esters with high optical purity and high yield from ketones by the combination of an enzyme catalyst and a metal catalyst without additional acyl donors, thereby resolving the problem caused by the use of excessive acyl donors.
• the invention provides a process for preparing chiral hydroxy esters by reacting a compound having both a ketone group and an acyloxy group in a molecule; a hydrogen donor which reduces the ketone into a hydroxy group; a metal complex, which catalyzes both the reduction of the ketone group and racemization of produced hydroxy group; and an enzyme, which catalyzes enantioselective acyl transfer in a suitable organic solvent.
• Formula 1 represents the chiral hydroxy ester.
• Formula 2 represents the substrate compound having both a ketone and an acyloxy group.
• Ri and R 3 independently represent substituted or unsubstituted C ⁇ - ⁇ 5 alkyl group, substituted or unsubstituted C ⁇ - ⁇ 5 akenyl group, substituted or unsubstituted C ⁇ - ⁇ 5 alkynyl group, substituted or unsubstituted C 6 - ⁇ 5 aryl group, substituted or unsubstituted Ci-1 5 heteroaryl group, substituted or unsubstituted C 4 - ⁇ 5 cycloalkyl group, substituted or unsubstituted C - ⁇ 5 heterocycloalkyl group or substituted or unsubstituted C 2 - ⁇ 5 heteroarylalkyl group.
• R 2 represents substituted or unsubstituted C 1 - 15 alkylene group, substituted or unsubstituted C 6 - ⁇ 5 arylene group, substituted or unsubstituted C - ⁇ 5 heteroarylene group, substituted or unsubstituted C - ⁇ 5 cycloalkylene group, substituted or unsubstituted C - ⁇ 5 heterocycloalkylene group, or substituted or unsubstituted C 2 - ⁇ 5 heteroarylalkylene group.
• Ri and R , R 2 and R , R ⁇ and R 3 may be linked to each other.
• the metal complex is a ruthenium complex represented by Formula 3.
• Yi, Y , Y 3 , Y 4 , Y 5 , Y 6 , Y 7 and Y 8 each independently represent substituted or unsubstituted C ⁇ - 10 alkyl group, substituted or unsubstituted C 6 - ⁇ 5 aryl group, substituted or unsubstituted CM S heteroaryl group.
• a chiral hydroxy ester is prepared by multi-step catalytic reactions in which an enzyme and a metal complex are used to induce asymmetrical reduction and transformation reaction.
• a substrate having both ketone group and acyloxy group as represented by Formula 2 a substrate having both ketone group and acyloxy group as represented by Formula 2; a ruthenium complex as represented by Formula 3, which reduces the ketone group and catalyzes the racemization of hydroxyl group; a hydrogen donor to reduce the ketone group; and an enzyme that catalyzes enantioselective acylation of one enantiomer of the racemic alcohols obtained by the racemization of hydroxyl group.
• Ri and R 3 are independently selected from the group consisting of substituted or unsubstituted C 1 - 15 alkyl group, substituted or unsubstituted C 1 - 15 akenyl group, substituted or unsubstituted C ⁇ - ⁇ 5 alkynyl group, substituted or unsubstituted C 6 - ⁇ 5 aryl group, substituted or unsubstituted C - ⁇ 5 heteroaryl group, substituted or unsubstituted
• R 2 is selected from the group consisting of substituted or unsubstituted C ⁇ - ⁇ 5 alkylene group, substituted or unsubstituted C 6 - ⁇ 5 arylene group, substituted or unsubstituted C 1 - 15 heteroarylene group, substituted or unsubstituted C - ⁇ 5 cycloalkylene group, substituted or unsubstituted C 4 - ⁇ 5 heterocycloalkylene group, and substituted or unsubstituted C 1 - 15 heteroarylalkylene group.
• Ri and R , R and R 3 , and Ri and R 3 may be linked to each other.
• Examples of linking formation are substituted or unsubstituted fused ring of 7-20 carbon atoms or substituted or unsubstituted hetero fused ring of 5-20 carbon atoms.
• the chemical compound of Formula 2 has both ketone and acyloxy groups and is preferably represented by Formulas 4 or 5.
• R 4 represents an Ci-10 alkyl group or an alkyl group with substituted heteroatoms
• R 5 represents C 1 . 5 alkyl group, C 2 - 5 alkenyl group, or C 2 - 5 alkynyl group
• m represents an integer between 1 to 6
• X represents halogen atom, C 1 - 5 alkyl group, C 2 - 5 alkenyl group, C 1 - 5 alkoxy group, nitro group, amide group, sulfonyl group or more
• thioalkoxy group represents C 6 - ⁇ o aryl group or Ci- 10 heteroaryl group.
• Formulas 4 and 5 include Formulas 4a through 4d or Formulas 5 a through 5d. [Formula 4a]
• Examples of unsubstituted C ⁇ - ⁇ 5 alkyl group include methyl, ethyl, propyl, isobutyl, sec-butyl, pentyl, iso-amil and hexyl. More than one hydrogen atom in such alkyl group may be substituted with halogen atom, halide, hydroxy group, nitro group, cyano group, amino group, amidino group, hydrazine, hydrazone, carboxyl group, sulfonic acid group, phosphoric acid group, lower alkyl group with 1 to 15 carbon atoms, and lower alkoxy group with 1 to 15 carbon atoms.
• the unsubstituted C 1 -1 5 alkenyl or unsubstituted Ci-is alkynyl group refers to an alkyl group containing double or triple carbon bonding in the middle or at the end of the chain. Examples thereof include ethylene, propylene, butylene, hexylene and acetylene. More than one hydrogen atom in such alkenyl or alkynyl groups may be substituted with the same substituents as listed for the C 1 - 15 alkyl group.
• Examples of the unsubstituted C 1 - 15 alkylene group include methylene, ethylene, propylene, isobutylene, sec-butylene, pentylene, iso-amilene and hexylene. More than one hydrogen atom in the alkylene group may be substituted with the same substituents as listed for the C ⁇ - ⁇ alkyl group.
• the aryl group refers to C 6 - 3 o carbocycle aromatic system in one or more ring structure, which may be used solely or in a combination. These rings may be held together by pendant method or fused together. Examples of aryl include phenyl, naphtyl, tetrahydronaphtyl, indenyl and biphenyl. More than one hydrogen atom in these aryl groups may be substituted with the same substituents as listed for the C ⁇ - ⁇ 5 alkyl group.
• the arylalkyl group is formed when one or more of the hydrogen atoms of the aryl group are substituted with lower alkyl radicals, such as methyl, ethyl or propyl radicals. Examples include benzil and phenylethyl. More than one hydrogen atom in the arylalkyl group may be substituted with the same substituents as listed for the d- ⁇ 5 alkyl group.
• the heteroaryl group refers to a mono- or bicyclic aromatic group which includes 1, 2, 3 or 4 heteroatoms chosen from N, O, P and S. Also, the heteroaryl group refers to a mono- or bicyclic aromatic group in which heteroatom is oxidized or alkylated to form an oxide such as N-oxide or a quaternary amine salt.
• Examples thereof include thienyl, benzothienyl, pyridyl, pyrazinyl, pyramidmyl, pyridazinyl, quinolinyl, quinoxalinyl, imidazolyl, furanyl, benzofuranyl, thiazolyl, isoxazolyl, benzisoxazolyl, benzimidazolyl, triazolyl, pirazolyl, pyrolyl, indolyl, 2-pyridonyl, 4- pyridonyl, N-alkyl-2-pyridonyl, pyrazinonyl, pyridazinonyl, pyrimidinonyl, oxazolonyl, corresponding N-oxides (for example, pyridyl N-oxide and quinolinyl N-oxide) and quaternary salts thereof but are not limited only to the ones specified. More than one hydrogen atom in the heteroaryl group may be substituted
• the heteroarylalkyl group refers to a heteroaryl group in which hydrogen atoms are partially substituted with alkyl groups. More than one hydrogen atom in the heteroarylalkyl group may be substituted with the same substituents as listed for the d- is alkyl group.
• the cycloalkyl group refers to a monocyclic group including 4 to 15 carbon atoms. More than one hydrogen atom in the cycloalkyl group may be substituted with the same substituents as listed for the C1-15 alkyl group.
• the heterocycloalkyl group refers to a monocyclic aromatic group, which includes 1, 2, 3 or 4 heteroatoms chosen from N, O, P or S. More than one hydrogen atom in the heterocycloalkyl group may be substituted with the same substituents as listed for the C 1 - 15 alkyl group.
• the ruthenium complex of the Formula 3 reduces ketone group of the Formula 2 and simultaneously catalyzes the racemization reaction of hydroxyl obtained from the reduction.
• the complex preferably has a phenyl group or a methyl group in all Yi to Y 8 groups.
• the amount of the ruthenium complex per 1 mole of the compound of Formula 2 is preferably 0.01 to 0.05 mol. More preferably 0.02 to 0.04 mol. When the amount is less than 0.01 mol, the reaction is excessively slow, and when the amount is greater than 0.05 mol, the production cost of chiral ester is high.
• Lipase is an enzyme that hydrolizes ester, and selectively acylates one of the enantiomers of the racemic alcohol to produce chiral ester with high optical purity.
• lipase Pseudomonas cepacia lipase(LPS), Candida antarctica lipase(CAL) and Candida rugosa lipase(CRL).
• Immobilized LPS and immobilized CAL B are preferable.
• the amount of the immobilized lipase is 0.5 to 20 mg per 1 mmol of the substrate, but preferably 1 to 10 mg.
• Hydrogen donor reduces the ketone group of Formula 2 to hydroxyl group in the presence of the catalyst of the ruthenium complex of Formula 3.
• One or more of such hydrogen donor is selected from the group consisting of hydrogen, formic acid, and alcohol of Formula 6.
• the alcohol of Formula 6 has alkyl side-chain not to be affected by enzyme. Examples thereof are 2,4-dimethyl-3- ⁇ entanol and 2,6-dimethyl-4-he ⁇ tanol.
• hydrogen under the atmospheric pressure is used as the hydrogen donor because of easiness in removal after reaction.
• the amount of hydrogen donor is preferably 1 to 50 mol per 1 mol of the compound of Formula 2.
• apro tonic solvent such as benzene, toluene, hexane, tetrahydrofuran, dioxan, C 2 - ⁇ o dialkyl ether (e.g., diethyl ether), C 3 - ⁇ o alkylacetate (e.g., ethyl acetate), acetonitrile, acetone, dicloromethane, cloroform, and carbon tetrachloride.
• benzene, toluene, hexane, tetrahydrofuran, dioxan C 2 - ⁇ o dialkyl ether (e.g., diethyl ether), C 3 - ⁇ o alkylacetate (e.g., ethyl acetate), acetonitrile, acetone, dicloromethane, cloroform, and carbon tetrachloride.
• the suitable amount of the solvent is controlled between 0.2 to 0.4 M based on the substrate used.
• appropriate temperature of the reaction varies depending on the ruthenium catalyst, preferably, the temperature is 50 to 100° C and more preferably 70 to 80° C. At temperature below 50° C, the racemization reaction is slow, but at temperature above 100° C, the enzyme rapidly loses its activity.
• Equation 1 illustrates the multi-step reaction of one of the representative examples.
• Equation 1 The product of the above Equation 1 is useful as an intermediate for chiral medicines such as rivastigmine.
• Table 1 shows the yield and optical purity of chiral esters prepared according to Experiments 1 to 8. The yield was determined by H-NMR and the optical purity was analyzed by High Performance Liquid Chromatography (HPLC) equipped with chiral column.
• HPLC High Performance Liquid Chromatography
• chiral hydroxy esters are obtained with high optical purities and yields from substrates with various structures, all having both ketone and acyloxy groups in a molecule.
• the invention demonstrates that the synthesis of chiral compound by enzyme/metal catalyzed multi-step reaction can be executed in single reaction chamber.
• the chiral hydroxy ester prepared by the invention is useful as an intermediate compound in production of agricultural chemicals, medicines and natural chemical compounds.
• the chiral hydroxy ester of Formula la prepared by the method according to the invention, is exceptionally useful as an intermediate compound in preparing a medicine such as rivastigmine.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Zoology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Microbiology (AREA)
• General Chemical & Material Sciences (AREA)
• Biotechnology (AREA)
• Health & Medical Sciences (AREA)
• Biochemistry (AREA)
• Bioinformatics & Cheminformatics (AREA)
• General Engineering & Computer Science (AREA)
• General Health & Medical Sciences (AREA)
• Genetics & Genomics (AREA)
• Analytical Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=32226220

Family Applications (1)

Country Status (2)

Citations (4)

Family Cites Families (2)

• 2002
  • 2002-10-31 KR KR10-2002-0067058A patent/KR100462473B1/ko not_active IP Right Cessation
• 2003
  • 2003-07-21 WO PCT/KR2003/001437 patent/WO2004039998A1/en not_active Application Discontinuation

Patent Citations (4)

Also Published As

Similar Documents

Legal Events