Investigation of imidazo[1,2-a]benzimidazole derivatives

Esters of 1-alkyl- and 1-aralkyl-2-iminobenzimidazoline-3-acetic acids are converted to esters of 2,9-dimethylimidazo[1,2,-a]benzimidazole-3-carboxylic acid on heating with acetic anhydride. The brief action of acetic anhydride on the free iminobenzimidazolineacetic acids gives 2-oxo-2,3-dihydroimidazo[1,2-a]benzimidazoles, which are converted to 2,9-substituted 3-acetylimidazo[1,2-a]benzimidazoles on prolonged heating with acetic anhydride.See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 111–114, January, 1973.