Greener synthesis using hydrogen peroxide in ethyl acetate of alicyclic ring-fused benzimidazoles and anti-tumour benzimidazolequinones

Abstract Environmentally-friendly and cost effective hydrogen peroxide in ethyl acetate was used to prepare in high yields pyrrolo[1,2- a ]benzimidazoles from commercial o -(pyrrolidin-1-yl)anilines without the requirement for organic-aqueous extraction and chromatography. Six, seven and eight membered ring-fused analogues were similarly obtained in high yields with methanesulfonic acid required for the pyrido[1,2- a ]benzimidazole. Anti-tumour benzimidazolequinone derivatives were obtained in high yield via the cyclization of 3,6-dimethoxy-2-(cycloamino)anilines.