Heteroaromatic analogues of 1,5-diarylpyrazole class as anti-inflammatory agents

Abstract

A novel series of heteroaromatic analogues of known anti-inflammatory (AI) drug celecoxib replacing the benzenesulfonamide moiety with 6-sulfonamidobenzothiazol-2-yl moiety was synthesized. Regioselective synthesis of the target compounds 2a–i having 1,5-diaryl relationship was achieved by exploring reaction conditions. All the newly synthesized compounds (2a–i and 8) were screened for their in vivo AI activity using carrageenan-induced rat paw edema assay. Five compounds (2c–f and 2i) were found to possess good AI activity (≥60% inhibition), 3 h after the carrageenan injection when compared to that of standard drug indomethacin (78%), whereas the remaining four compounds (2a–b and 2g–h) with 1,5-diaryl relationship have shown moderate activity with 49–56% inhibition after 3 h. However, pyrazole 8 having 1,3-diaryl relationship failed to show appreciable AI activity.