Synthesis and xanthine oxidase inhibitory activities of 2-phenyl-tetrahydrothiopyrano［4, 3-d］ pyrimidine derivatives

Twelve novel 2-phenyl -tetrahydrothiopyrano［4, 3-d］pyrimidine derivatives were synthesized from 4-hydroxy-benzonitrile by etherification, hydrolysis, acylation and addition reactions, etc. The inhibitory activities against xanthine oxidase were evaluated in vitro. Results showed that compounds 8a-8h exhibited varying inhibitory potencies on xanthine oxidase at 100 μmol/L, significantly better than those of compounds 6a-6d , indicating that carboxy-substituted pyrimidine is beneficial to the inhibitory activity. Among compounds 8a-8h , 8f with isopropionic acid-substituted pyrimidine and ethyl-substituted phenol showed the best inhibition with IC₅₀ of 76. 0 μmol/L.