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

Immobilised lipase from Candida antarctica catalyses the enantioselective esterification of (±)-ketoprofen. The reaction conditions of the kinetic resolution have been investigated. The use of methanol in dichloropropane allowes to realise a large scale separation, giving the desired enantiopure S-ketoprofen as unreacted enantioform. The R-enantiomer, recovered as ester, easily undergoes chemical racemisation and can be recycled and reused in the process.