Process for preparing (-)menthol and similar compounds

• Main Authors: MADRIE PORTWIG, CHRISTOPHER JOHN PARKINSON, ANDREW MBONISWA BUTANA, ROBIN KUMAR MITRA, MELANIE DARYL EVAN DICKSON, DEAN BRADY, NEIL STOCKENSTROM GARDINER, SHAVANI REDDY, JENNIFER ANN CHAPLIN, STEPHANUS FRANCOIS MARAIS
• Format: Patent
• Language: English
• Published: 21.01.2002
• Edition: 7
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; APPARATUS THEREFOR; BEER; BIOCHEMISTRY; CHEMISTRY; ENZYMOLOGY; FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIREDCHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERSFROM A RACEMIC MIXTURE; GENERAL METHODS OF ORGANIC CHEMISTRY; METALLURGY; MICROBIOLOGY; MUTATION OR GENETIC ENGINEERING; ORGANIC CHEMISTRY; SPIRITS; VINEGAR; WINE

A process of separating a single desired stereoisomer from a racemic mixture of eight stereoisomers of a compound of formula (III), wherein R1 represents an isopropanol group, an isopropyl group or an isopropylene group, includes the steps of: contacting the racemic mixture in a suitable organic solvent with an esterifying agent and a stereospecific enzyme which stereoselectively esterifies the -OH group of the desired stereoisomer, for a time sufficient to convert a desired percentage of the desired stereoisomer to a compound of formula (IV), wherein R1 is as defined above and R4 is an alkyl or an aryl group, to give a first reaction product including the compound of formula (IV), the organic solvent, the unconverted stereoisomers of the compound of formula (III), excess esterifying agent and by-products of the reaction; and separating the compound of formula (IV) from the first reaction product. The process is of particular application for the production of (-)-menthol