[Stereoselective synthesis and pharmacological properties of metabolites of new antiinflammatory agent. 4'-Acetyl-2'-(2,4-difluorophenoxy)methanesulfonanilide (FK3311)]

Asymmetric reduction of acetophenone (FK3311: 1) and ethyl phenylglyoxylate (7) with various chiral reducing agents was investigated in an attempt to synthesize both optical isomers of the two metabolites (2 and 5) of 1. The treatment of 1 with 3,3-diphenyl-1-methyltetrahydro-1H,3H-pyrrolo[1,2-c]-[1,3,2]- oxazaborolidine-borane complex (reductants B, C) gave chiral alcohol 2 in a high optical purity. On the other hand, reduction of 7 by B-chlorodiisopinocamphenylborane (reductants E, F) gave the best result among the tested reagents. Each isomer of 2 and 5 was examined for in vitro activity to inhibit zymosan-induced prostaglandine E2 production, adjuvant-induced arthritis for antiinflammatory activity, and acetic acid-induced writhing for analgesic activity in comparison with the racemic mixture.