Novel benzo[d]imidazole-2(3H)-thiones as potent inhibitors of the α-melanocyte stimulating hormone induced melanogenesis in melanoma B16 cells

Abstract

In order to determine the optimum size of heterocycle of lead compound 1 (6-methyl-3-phenethyl-3,4-dihydro-1H-quinoline-2-thione; IC50=0.8 μM) for inhibition of melanogenesis, we have synthesized and evaluated some benzimdazole-2(3H)-thiones 5a - e. The preliminary bioassay has shown that the benzimdazole-2(3H)-thione motif of 5 is essential structural unit for their inhibitory activity. Among all thiones 5a - e, the compound 5d strongly inhibited the formation of melanin with IC50 value of 1.3 μM. © 2010 Pharmaceutical Society of Japan.