Stereoselective synthesis of (S)-(+)-naproxen catalyzed by carboxyl esterase in a multicompartment electrolyzer

The stereoselective hydrolysis of racemic 2-substituted propionates, cataly zed by carboxyl esterase, provides a cost-competitive route to produce the optically pure, anti-inflammatory drug Naproxen, In the present work, we de scribe the application of the multicompartment electrolyzer reactor (ME) fo r the stereoselective hydrolysis of a racemic Naproxen ester, (R,S)-ethoxye thyl-[2-(6-methoxy-2-naphtyl)]propionate, catalyzed by a carboxyl esterase. The enzyme was trapped in a reactor chamber, delimited by two isoelectric m embranes encompassing the pi value of the enzyme, together with the neutral substrate. After 90 min, a conversion of 45% was obtained with an enantiom eric excess of 84%. The reaction product, (S)-(+)-Naproxen, was electrophor etically removed in continuous from the reaction chamber and collected in a contiguous, more acidic chamber, separated from the enzyme and from the un reacted substrate. Moreover, at the end of the reaction, it was possible to recover the enzyme from the reactor and use it again. (C) 2001 Elsevier Sc ience B.V. All rights reserved.