Synthesis, Biological Evaluation, and Molecular Docking Studies of Hydrazones as Novel Xanthine Oxidase Inhibitors

A series of hydrazones, 2-cyano-N'-(4-diethylamino-2-hydroxybenzylidene)acetohydrazide (1), N'-(5-bromo-2-hydroxy-3-methoxybenzylidene)-3-chlorobenzohydrazide monohydrate (2·H2O), N'-(2-hydroxy-3-methylbenzylidene)-4-nitrobenzohydrazide (3), and N'-(2-hydroxy-3-trifluoromethoxybenzylidene)-4-nitrobenzohydrazide (4), were prepared and structurally characterized by elemental analysis, IR and 1H NMR spectra, and single crystal X-ray determination. Xanthine oxidase inhibitory activities of the compounds were studied. Among the compounds, 2-cyano-N'-(4-diethylamino-2-hydroxybenzylidene)acetohydrazide shows the most effective activity. Docking simulation was performed to insert the compounds into the crystal structure of xanthine oxidase at the active site to investigate the probable binding modes.