| 摘要 |
A stereospecific process for the preparation of a pharmaceutically active compound in at least 70% by weight S-configuration of the formula <CHEM> or a pharmaceutically acceptable salt or ester thereof, wherein R1 represents an optionally substituted aryl group such as a phenyl or naphthyl group, or R1 represents a heterocyclic ring system, which is optionally substituted, or R1 represents a heteroaromatic ring system optionally containing in addition to carbon atoms one or more atoms of nitrogen, sulphur or oxygen atoms, this ring system being optionally substituted, comprises subjecting a compound of the formula <CHEM> wherein R2 is an alkyl group containing at least 3 carbon atoms, to the action of a micro-organism or substances derived therefrom capable of stereoselective oxidation of compound (II) into compound (I), having at least 70% by weight S-configuration. |
