Synthesis and bioevaluation of 2-phenyl-5-methyl-2H-1,2,3-triazole-4-carboxylic acid/carbohydrazide derivatives as potent xanthine oxidase inhibitors

A series of 2-phenyl-5-methyl-2H-1,2,3-triazole-4-carboxylic acids/carbohydrazides as analogues of febuxostat were synthesized and evaluated for their in vitro xanthine oxidase (XO) inhibitory activity. Among these compounds, the carboxylic acid derivatives 7a–h and 8a–h exhibited high potency in the submicromolar/nanomolar range. Steady-state kinetics experiment revealed that 7f was a mixed-type inhibitor of xanthine oxidase. In addition, a molecular docking study of 7f was performed to determine its binding mode at the active site of xanthine oxidase.