In view of expanding the structure activity relationship of xanthineoxidaseinhibitors, a series of 3-oxo-6-aryl-2,3-dihydropyridazine-4-carbohydrazide/carboxylic acid derivatives were designed by molecular docking and synthesized. All the target compounds were evaluated for their in vitro XO inhibition by using febuxostat and allopurinol as the standard controls. Most of the hydrazide derivatives
A number of 5-phenylisoxazole-3-carboxylic acid derivatives (5a-e, 11a-e) were synthesized and analyzed for their ability to inhibit xanthine oxidase. Most of the compounds exhibited potency levels in the micromolar/submicromolar range. The presence of a cyano group at the 3-position of phenyl moiety turned out to be the preferred substitution pattern, as its transformation into the nitro group determined a general reduction of the inhibitory potency. A molecular modeling study on compound 11a was performed to gain an insight into its binding mode with xanthine oxidase, and to provide the basis for further structure-guided design of new non-purine xanthine oxidase inhibitors related with 5-phenylisoxazole-3-carboxylic acid scaffold.