ENZYMATIC ACYLATION IN THE RESOLUTION OF METHYL THREO-2-HYDROXY-3-(4-METHOXYPHENYL)-3-(2-X-PHENYLTHIO)PROPIONATES IN ORGANIC-SOLVENTS

A practical lipase PS (Pseudomonas cepacia)-catalysed resolution of methyl threo-2-hydroxy-3-(4-methoxyphenyl)-3-(2-X-phenylthio)propionates 3, the (2S,3S)-enantiomers of which are important intermediates in the diltiazem synthesis, has been performed using acetone oxime, and isopropenyl or vinyl acetates as acylating reagents in organic solvents. The substituent X in compounds 3 does not have a clear effect on the enzymatic enantioselectivity, but the time needed for the resolution depends on X. The immobilization of the enzyme on Celite or Chromosorb in the presence of sucrose greatly enhances enzymatic activity. The immobilized enzyme is stable for reuse.