Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D11/00—Solvent extraction
  • B01D11/02—Solvent extraction of solids
  • B01D11/0203—Solvent extraction of solids with a supercritical fluid
• • 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
• • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids

Definitions

• the object of the present invention is a production method for optically active 5 isomers of chiral compounds wherein enzymes catalyze a reaction between a chiral and a non-chiral starting material in supercritical carbon dioxide so that mainly only one of the optically active isomers of the chiral starting material reacts and produces a new chiral product which has a higher enantiomeric purity than the optical purity of the starting material.
• the non-desired enantiomers of a racemic mixture are often without any 20 pharmaceutical effect. Some may cause side effects and in the worst case they may be poisonous. Apparently the major part of chiral pharmaceuticals and agrochemicals should be produced and used as pure optical isomers. New legislation and development of new, more economical production techniques bring demands and possibilities particularly to produce new chiral 25 pharmaceuticals as pure optical isomers.
• Liquid chromatography where a mixture of organic solvents are used as the eluent is 5 available for this purpose.
• Several chiral stationary phases may be used. However, a general purpose chiral stationary phase has not been developed. Therefore a specific chiral separation method has to be developed for each separation case.
• a liquid chromatographic production method one has to use large amounts of organic solvents which are flammable, they pose an occupational health risk and they require extensive precautions to avoid environmental problems. They also leave small solvent residues in the products.
• the desired optically pure product has to be separated from the eluent by evaporating the solvents. The solvents have to be purified prior to reuse by distillation which consumes large amounts of energy.
• Supercritical carbon dioxide is defined as carbon dioxide in the state where its temperature is higher than the critical temperature (32 C) and pressure higher than the critical pressure (72 bar). In this supercritical state carbon dioxide can be used as solvent for volatile and hydrophobic compounds. Supercritical carbon dioxide is a non-toxic, non-flammable and relatively cheap solvent. By using supercritical carbon dioxide as reaction medium one can avoid the occupational protection and effluent problems and the risks of fire associated with the use of large amounts of organic solvents. A further advantage is that the recovery of carbon dioxide for reuse consumes only a fraction of the energy which is required to recover organic solvents by distillation.
• the purpose of the present invention is to provide a new, more economical method for the production of optically active isomers of chiral compounds.
• the object of the invention is a method wherein, differing from previous methods, supercritical carbon dioxide is used as a reaction medium in enzymatically catalyzed enantiomerically specific reactions.
• the advantages of the present invention include that only one, non-flammable, non-toxic and cheap solvent, carbon dioxide, is used as solvent for the starting materials, as a reaction medium in enzymatically catalyzed enantiomerically specific reactions and possibly also in the fractionation of the reaction mixture and in the purification of the products.
• Another advantage of the present invention is that carbon dioxide provides an atmosphere which protects the starting materials and products from oxidation.
• a further advantage of the present invention is that the solvent power of supercritical carbon dioxide can be tuned. By this we mean that the solvent power of supercritical carbon dioxide is strongly dependent on its density. This property makes it possible to precipitate the reaction mixture from supercritical carbon dioxide simply by lowering the pressure of the supercritical solution.
• a still further advantage of the present invention is that supercritical carbon dioxide has very good mass-transfer properties compared to liquid solvents. This property of carbon dioxide accelerates the dissolution of starting materials and promotes the reactions which are controlled by mass transfer.
• Another advantage of the present invention is that the production process is virtually closed. There are no solvent effluents, the production of waste water is very small, the process, is well protected from external microbe 5 contamination and the parts of the process may be easily sterilized when necessary. Carbon dioxide does not leave any harmful solvent residues.
• One advantageous embodiment of the invention is the resolution of a racemic mixture of a chiral compound.
• the racemic mixture and a non-chiral reagent are brought to contact with enzymes so that principally only one of the enatiomers of the racemic mixture reacts.
• the obtained chiral reaction product is enantiomerically pure and is physico-chemical ly so different from the racemic mixture that it can be separated from the reaction mixture by conventional methods. For example by extraction, crystallization or evaporation. Other optically pure compounds can then be produced from the obtained enantiomerically pure product by conventional chemical methods.
• a still further advantage of the present invention when compared to e.g. resolution made with chiral reagents, is that cheap, simple compounds like carboxylic acids or alcohols can be used instead of the expensive chiral reagents.
• a lipase (EC 3.1.1.3) produced by Mucormieh ⁇ i yeast, immobilized on a ionexchange resin, was weighed into a 250 ml pressure vessel, which was closed and rinsed with atmospheric pressure carbon dioxide to remove air.
• the pressure vessel was warmed to 50 C and it was pressurized with carbon dioxide to 150 bar.
• 0.3 cc water was fed to the pressure vessel with carbon dioxide along with 45 mmol racemic ibuprofen and 105 mmol propanol, butanol or amylalcohol.
• the contents of the pressure vessel was agitated with a magnetic stirrer. Small samples of the reaction mixture were taken during the reaction and they were analyzed using gas chromatography and liquid chromatograhy using chiral packed columns.
• the contents of the pressure vessel was directed through a pressure reduction valve into another vessel which was kept in atmospheric pressure.
• the components of the reaction mixture precipitated from carbon dioxide. They formed droplets which settled to the bottom of the vessel.
• the carbon dioxide which was the solvent for the reaction mixture evaporated and was removed from the top of the vessel.
• esterification rate of the S-enantiomer of ibuprofen with these alcohols was approximately nine times the rate of esterification of the R-enantiomer of ibuprofen.
• example 1 The procedure of example 1 was repeated varying the amount of water which was fed to the reactor along with carbon dioxide. This was done to find the optimum moisture for the reaction rate and selectivity.
• Starting materials for the reaction were racemic ibuprofen and propanol.
• the results are collected in table 2. According to the results an advantageous water content for the reaction rate is 0.35 - 1.3 mL water in a litre of carbon dioxide. The water content had no effect on the enantiomeric purity of the produced ibuprofen ester.
• the advantageous propanol excess was 3 - 16 mol propanol / mol ibuprofen.
• the propanol excess had no decisive effect on the enantiomeric purity of the obtained S-ibuprofen ester.
• Example 7 The procedure of example 1 was repeated except that 45 mmol 2-octanol was used as the chiral, racemic starting material and 105 mmol hexanoic acid as the non-chiral reagent.
• the production rate of the produced ester was 12.5 mmol ester per kg lipase and hour.
• the enantiomeric purity of the obtained R-2-octylester was 84 % when 50 % of the racemic 2-octanol had reacted.
• Example 7 The procedure of example 1 was repeated except that 45 mmol 2-octanol was used as the chiral, racemic starting material and 105 mmol hexanoic acid as the non-chiral reagent.
• the production rate of the produced ester was 12.5 mmol ester per kg lipase and hour.
• the enantiomeric purity of the obtained R-2-octylester was 84 % when 50 % of the racemic 2-oct
• example 1 The procedure of example 1 was repeated except that 45 mmol ibuprofen propylester was used as the chiral, racemic starting material and 105 mmol amylalcohol as the non-chiral reagent.
• the rate of the alcoholysis reaction was 17.5 mmol ibuprofen amylester per kg lipase and hour.
• the enantiomeric purity of the obtained S-ibuprofen amylester was 81 % when 25 % of the racemic starting material had reacted.

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• Preparation Of Compounds By Using Micro-Organisms (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (3)

• 1991
  • 1991-05-16 FI FI912377A patent/FI90995C/fi active IP Right Grant
• 1992
  • 1992-05-14 WO PCT/FI1992/000151 patent/WO1992020812A1/en not_active Application Discontinuation
  • 1992-05-14 EP EP92909747A patent/EP0588809A1/en not_active Withdrawn

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