4,6-Diaryl/heteroarylpyrimidin-2(1H)-ones as a new class of xanthine oxidase inhibitors

Summary A series of 4,6-diaryl/heteroarylpyrimidones was synthesized employing silica-supported fluoroboric acid under solvent-free conditions in a microwave reactor. The catalytic influence of HBF4-SiO2 was investigated in detail to optimize the reaction conditions. The synthesized compounds were evaluated for in vitro xanthine oxidase (XO) inhibitory activity for the first time. Structure-activity relationship analyses are also presented. Among the synthesized compounds, VA-5, -9, -10, -12, -22, -23, and -25 were the active inhibitors with IC50 values ranging from 6.45 to 13.46 μM. Compound VA-25 with a pyridinyl ring as ring A and a thiophenyl ring as ring B emerged as the most potent XO inhibitor (IC50 = 6.45 μM) in comparison to allopurinol (IC50 = 12.24 μM). Some of the important interactions of VA-25 with the amino acid residues of the active site of XO were figured out by molecular modeling studies. A series of 4,6-diaryl/ heteroarylpyrimidones, synthesized by silica supported fluoroboric acid under solvent-free conditions in a microwave reactor, were evaluated for their in vitro xanthine oxidase inhibitory activities. VA-5, -9, -10, -12, -22, -23, and -25 were found to be active inhibitors with IC50 values ranging from 6.45 to 13.46 μM. Structure-activity relationship analyses are also presented.