Large scale preparation of enantiopure S-ketoprofen by biocatalysed kinetic resolution.

Immobilised lipase from Candida antarctica (Novozym+ 435) catalyses the enantioselective esterification of (9/)-ketoprofen. The reaction conditions of the kinetic resolution have been investigated considering the kind of the solvent adopted and varying the nature of the alcohol. The use of methanol in dichloropropane allowes large scale separation, giving the desired S-ketoprofen with 96% ee as unreacted enantioform. The R-enantiomer, recovered as ester, easily undergoes chemical racemising hydrolysis and can be reused in the process