Design and Synthesis of Some 5-Substituted-2-(4-(azido or methylsulfonyl)phenyl)-1H-indole Derivatives as Selective Cyclooxygenase (COX-2) Inhibitors

A group of 5-substituted-2-(4-azido or (methylsulfonyl)phenyl)-1H-indoles were designed and synthesized as selective cyclooxygenase (COX-2) inhibitors. In vitro COX-1 and COX-2 isozyme inhibition studies were carried out to investigate the effect of different substituents (H, F, Cl, Me, OMe) at C-5 position and different pharmacophore groups (azido or methylsulfonyl) at para position of phenyl ring at C-2 position of the 1H-indole ring on COX-2 selectivity and potency. The structure-activity relationship study of these compounds indicated that the introduction of a methoxy substituent at C-5 position and 4-(methylsulfonyl) phenyl group at C-2 position of the 1H-indole ring (compound 4e) had the best COX-2 selectivity (S.I= 291.2). A molecular modeling study where 4e was docked in the binding site of COX-2 showed that the methylsulfonyl group at para position of phenyl ring is oriented in the vicinity of the COX-2 secondary pocket.