Synthesis and Antitumor Evaluation of New Heterocycles Derived from 3-Methyl-2-benzothiazolinone Hydrazone

3-Methyl-2-benzothiazolinone hydrazone condensed with some selected aldehydes to give the corresponding Schiff bases. Cyclizing the obtained Schiff base derivatives with thioglycolic acid afforded the respective thiazolylideneaminothiazolidenones. Condensation of 3-methyl-2-benzothiazolinone hydrazone with ethyl cyanoacetate yielded a mixture of the bishydrazine and the cyanoacetohydrazide derivatives. Meanwhile, its condensation with ethyl acetoacetate produced a mixture of the monoketone and the β-diketone derivatives. Besides, the reaction of the starting hydrazone with malononitrile afforded a mixture of the cyanomethylylidene and cyanomethyl hydrazone derivatives beside the bishydrazine derivative. Elementary and spectroscopic measurements were in good accord with the structures postulated for the new compounds. The antitumor activities of certain selected new compounds were screened, in vitro, against a panel of four (liver, HepG2; breast, MCF-7; lung, A549; and colon; HCT116) human solid tumor cell lines. The cells that showed better activity were HepG2 and MCF-7. Structure-activity relationship (SAR) was also discussed.