Preparation of (S)-naproxen by enantioselective hydrolysis of racemic naproxen amide with resting cells of Rhodococcus erythropolis MP50 in organic solvents

Racemic naproxen amide (RS)-1 was hydrolyzed to enantiomerically pure naproxen (S)-2 in water-saturated organic solvents with log P values between 2.0 and 0.17 using immobilized resting cells of the bacterial strain Rhodococcus erythropolis MP50. Alkyl acetates are the most suitable solvents concerning solubility of (RS)-1 and enzyme activity. In butyl acetate with 3 vol% DMSO as cosolvent and an increased water content of the immobilized cells the rate of hydrolysis was an optimum. Under these reaction conditions a preparative scale application gave after 45 h, at a conversion rate of 48%, (S)-2 with >99% ee and an isolated yield of 84%. (C) 1997 Elsevier Science Ltd.