Discovery and synthesis of novel allylthioaralkylthiopyridazines: their antiproliferative activity against MCF-7 and Hep3B cells.

A new series of 6-allylthio-3-aralkylthio-4,5-dimethylpyridazines 5a-5k and 1-allylthio-4-alkylthio-5,6,7,8-tetrahydrophthalazine 6a-6j was synthesized from maleic anhydride derivatives for development of new anticancer agents. The process involves the formation of pyridazine and phthalazine rings, dichlorination, allylthiolation, and aralkylthiolation. These new compounds showed antiproliferative activities against breast cancer (MCF-7) and hepatocarcinoma (Hep3B) cells in CCK-8 assays, and could be promising candidates for chemotherapy of carcinomas. Among 21 synthesized compounds, five compounds (5a, 5b, 6b, 6d, and 6f) showed higher potency than 5-FU for inhibiting the growth of cell line. The results indicated that compound 6f had the highest activity towards MCF-7 and Hep3B cells. These results suggest the potential anticancer activity of compounds 5a, 5b, 6b, 6d, and 6f.