Intramolecular amination of ortho-nitro-tert-anilines as a method for the synthesis of condensed benzimidazole derivatives with a nodal nitrogen atom

The paper examines the applicability limits of the intramolecular reductive cyclisation reaction of ortho-nitroarenes containing various limiting azagetherocycles for the synthesis of condensed benzimidazole derivatives with a nodal nitrogen atom. The process of intramolecular heterocyclisation occurred during the reduction of 4-(2-nitroaryl)-4-morpholine and 1-(2-nitroaryl)-4-methylpiperidine. At the same time, the presence of the 4-methyl-piperazine cycle in the substrate prevented the formation of a condensed polyazaheterocycle.