Abstract
Several new heterocyclic compounds such as benzimidazo[1,2-a]piperazine derivatives (5-7;9,10 and 14,15,17) have been synthesized by the reactions of the versatile 2-(1-methyl-1H-benzo[d]imidazol-2-yl)-2-nitrosoacetonitrile (2) with malononitrile derivatives (3a-e) and 2-cyanomethylbenzimidazole derivatives (1b,c). Oxidation of iminopyrazino[1,2-a]benzimidazole-3-carbothioamide derivatives 9 via refluxing in aqueous H2O2 solution afforded iminopyrazino[1,2-a]benzimidazole-3-carboamide derivatives 10. Also, reaction of 9 with 1-aryl-2-bromoethanone derivatives (11a,b) in refluxing DMF, the Hantzsch-type thiazoles (12a,b) were obtained. All newly synthesized compounds were elucidated by considering the data of both elemental and spectral analysis.