Synthesis and biological evaluation of 3-(trimethoxyphenyl)-2(3H)-thiazole thiones as combretastatin analogs.

A series of 3-(trimethoxyphenyl)-2(3H)-thiazole thiones 5 were designed as new heterocyclic analogs of combretastatin A-4 (CA-4). Indeed, the olefinic core structure of CA-4 has been replaced by 2(3H)-thiazole thione. The general synthetic strategy to prepare compounds 5 was based on the cyclocondensation reaction between triethylammonium N-(trimethoxyphenyl)dithiocarbamate and appropriate phenacyl halide. The cytotoxic activity evaluation of 3-(trimethoxyphenyl)-2(3H)-thiazole thiones 5 against human cancer cell lines T47D, MCF-7 and MDA-MB-231 demonstrated that 4-methyl analog 5f showed the highest activity against all cell lines. Compound 5f had no significant toxicity towards non-tumoral cells MRC-5 and its cytotoxicity was apparently selective for cancer cells. The results of bioassays showed that the representative compound 5f depolymerized tubulin, inhibited cell proliferation, and induced apoptosis in cancer cells.