Synthesis and antiproliferative activity in vitro of 2-aminobenzimidazole derivatives.

A novel series of Schiff bases 1-11, the derivatives of 2-aminobenzimidazole and substituted aromatic aldehydes, has been synthesised. Compounds 1-11 reduced by NaBH(4) formed 2-benzylaminobenzimidazoles 12-21. 2-(o-Bromobenzylamino)benzimidazole (15) acylated by cinnamoyl chloride gave 2-(o-bromobenzylamino)-1-cinnamoylbenzimidazole (22). Long heating of 15 and 19 with p-nitrocinnamoyl or cinnamoyl chloride led to the formation of pyrimido[1,2-a]benzimidazol-4-ones 23 and 24. The structures of 1-24 were identified by the results of elemental analysis and their IR, (1)H NMR and MS spectra. Among the compounds 1-24 evaluated for their antiproliferative activity in vitro, 16, 19, 20 and 22 exhibited cytotoxic activity against the cells of human cancer cell lines, namely SW707 (rectal), HCV29T (bladder), A549 (lung) and T47D (breast cancer).