Screening of a library of 4-aryl/heteroaryl-4H-fused pyrans for xanthine oxidase inhibition: Synthesis, biological evaluation and docking studies

A series of 4-aryl/heteroaryl-4H-fused pyrans was synthesized via multicomponent reaction in a microwave synthesizer. All the pyrans were evaluated for in vitro xanthine oxidase inhibition. Structure-activity relationship was also established. Among the series of 108 compounds, Compound 5n was the most potent displaying remarkable inhibition against the enzyme with an IC₅₀ value of 0.59 μM. Enzyme kinetic study was carried out for the compound 5n to determine the type of inhibition. The study revealed that the compound 5n was a mixed-type inhibitor. Molecular modelling studies were also performed to figure out the interactions of both the enantiomers of 5n with the amino acid residues of the enzyme.