Preparation of S-(+)-ketoprofen by coupling the enantioselective hydrolysis of ketoprofen methyl ester with the photo-oxidation of methanol

Abstract

A novel method for preparation of S-(+)-ketoprofen is presented involving coupling enantioselective hydrolysis of ketoprofen methyl ester catalyzed by a surfactant-coated-lipase with the photo-oxidation of methanol in a water-saturated organic solvent. The effect of photocatalytic conversion of methanol into water and carbon dioxide on the hydrolysis of ketoprofen methyl ester and the stability of the enzyme was investigated. The photo-oxidation of methanol shifted the equilibrium of the hydrolysis toward the formation of ketoprofen, increasing the equilibrium conversion ratio and improving the enantioselectivity. Because the surfactant-coated lipase and ketoprofen methyl ester dissolved in the organic solvent and ketoprofen was absorbed on the TiO₂ photocatalyst particles, the separation procedures could be simplified and the stability of the enzyme was increased.

• enantioselective hydrolysis
• photocatalysis
• S-(+)-ketoprofen
• surfactant-coated lipase

Notes

One of the referees suggested that the equations of Chen are invalid as they are based on a fixed equilibrium constant while in our case K′will vary with time. We agree that the equilibrium constant varies with time in our study as the referee stated, but we think it has a fixed value at a fixed time. Therefore, the equations of Chen et al. are still valid and they can be used to analyze our experimental data.