The synthesis and anticancer activity of some 1,2,3-trisubstituted pyrazinobenzimidazole derivatives

The synthesis of some new pyrazino[1,2-a]benzimidazole derivatives and investigation of their anticancer activities were aimed in this work. Thus, 2-acetylbenzimidazole was reacted with ? -bromoacetophenone derivatives and potassium carbonate in acetone to give 1-(2-phenyl-2-oxoethyl)-2-aryloyl-4,5-diarylimidazoles. These diketone compounds were reacted with appropriate benzylamine in acetic acid to obtain 1-methylene-2-benzyl-3-aryl-1,2-dihydropyrazino[1,2-a]benzimidazole derivatives. The structure of the compounds obtained were elucidated by using IR and 1H-NMR spectral data and elemental analysis results.All of the compounds were offered to American National Cancer Institute (NCI). Anticancer activities of the selected compounds were evaluated in vitro against approximately sixty human cell lines derived from nine neoplastic diseases and the results were given as growth percentage values. It was observed that the diketones were remarkable active compounds with low growth percentage. The most active compound was 1-[2-(3-chlorophenyl-2-oxoethyl)]-2-acetylbenzimidazole with the growth percentage of 24.53