Candida rugosa lipase catalyzed esterification of racemic ibuprofen with butanol: racemization of R-ibuprofen and chemical hydrolysis of S-ester formed

The chemical treatment of products obtained from Candida rugosa lipase catalyzed enantioselective esterification of racemic ibuprofen with n-butanol in isooctane was studied. After a complete separation of the unreacted R-ibuprofen from the S-ester formed, the R-ibuprofen was racemized and the S-ester was chemically hydrolyzed to S-ibuprofen with the same enantiomeric excess as that of the ester before hydrolysis. A cyclic process of preparing S-ibuprofen from its racemate with lipase catalysis in organic solvent is therefore feasible.