AbstractImprovement of stereoselective resolution of racemic Naproxen, 2‐(6‐methoxy‐2‐naphthyl)propionic acid, was attempted with esterifcation reaction byCandida cylindracealipase. By carefully selecting the organic medium, a 72‐time enhancement of yield of the desired S‐ester was achieved. The optimal reaction temperature was approximately 53°C, and an alcohol concentration between 20 mMand 40 mMin an 80% (v/v) isooctane and 20% (v/v) toluene mixture was found. © 1994 John Wi