Synthetic strategies and biological screening of novel pyrazolines as COX inhibitors

In this study, a novel series of pyrazolines was afforded by the reaction of 2-hydrazinyl-N-(4-aminosulfonylphenyl)acetamide (2) and chalcone intermediates. The structures of target compounds were confirmed by IR, 1H NMR, 13C NMR and HRMS. The synthesized compounds were further evaluated for their in vitro COX inhibitory activity in order to discover new, effective and safer anti-inflammatory agents. Most of the compounds were more selective for COX-2 isozyme than COX-1. All compounds were weak inhibitors when compared to standard drugs ibuprofen, celecoxib and nimesulide. Among them, compounds 4a, 4e and 4f were the most potent inhibitors of COX-2. These findings suggest that these compounds could be lead compounds for further development as selective COX-2 inhibitors.