| abstract |
Racemic 2-alkoxy-, and 2-(aryl-alkoxy)- propionic acids of general formula CH3-CH(OR1)-COOH (I) (where R1 = 1-6C alkyl-, alkenyl-, phenyl-, mono- or multi-substd, phenyl gp.), are resolved into (S) and (R) optical isomers by enzyme catalysed asymmetric esterification, followed by sepn. of the optically active ester and optically active unreacted acid. Asymmetric esterification takes place in the reaction mix which contains 0.002-2% initial water, using an aliphatic alcohol and in the medium of an aliphatic solvent sparingly miscible with water. - An initial acid:alcohol molar ratio = 1:0.05-1:20 is maintained. Esterification is catalysed by a stereospecific lipase enzyme which is stable in the relevant solvent and is either in free or fixed state. A 5-60 deg.C reaction temp. is used |