A series of compounds comprising the thiocarboximidopyrazolyl 5, the phenylpyrazolyl 6, the dimethylpyrazolyl 7, the nitrophenylpyrazolyl 8, the dimethyloxazolyl 9, the benzoxazepinyl 10, and pyrimidyl 11 a-c derivatives of 3-(2-methyl-1H-benzimidazol-5-ylazo)pentane-2, 4-dione was synthesized. Moreover, 5-amino-2-methylbenzimidazole (3) was reacted with phthalic anhydride or maleic anhydride in acetic acid or in toluene to produce 12-15. Treating 5, 6-diamino-2-methylbenzimidazole (16) with ethyl cyanoacetate or diethyl malonate or acetyl acetone leads to the formation of the benzodiazepine derivatives 17-20. The cytotoxic activity of the compounds 2, 7, 9, 10, and 11 was tested against 60 types of human cancer cell lines. Compounds 7 and 9 were found to be the most potent.

Synthesis of 5-Substituted 2-Methylbenzimidazoles with Anticancer Activity. -A variety of new 2-methylbenzimidazole derivatives such as (III), (V), (VII), (VIII) and (XI) are synthesized and evaluated for their cytotoxicity against human cancer cell lines. The compounds (VIII) are found to be the most active ones. -(EL-NAEM*, S. I.; EL-NZHAWY, A. O.; EL-DIWANI, H. I.; ABDEL HAMID, A. O.; Arch.