Design, synthesis and biological evaluation of hydroxy- or methoxy-substituted 5-benzylidene(thio) barbiturates as novel tyrosinase inhibitors

A series of hydroxy- or methoxy-substituted 5-benzylidene (thio)barbiturate derivatives were designed, synthesized, and evaluated as novel tyrosinase inhibitors. Compound 1e were found to be the most potent inhibitor. SARs were discussed and the inhibition mechanism of selected compounds 1e and 2e was also investigated.