Studies on Benzimidazoles and Related Compounds. III. The Intramolecular Mannich Reaction of 2-Alkylaminomethylbenzimidazoles

Abstract

The intramolecular Mannich reaction of 2-alkylaminomethylbenzimidazole (II) provided 4-alkyl-1, 3, 4, 5-tetrahydro-1, 3, 6-oxadiazepino [3, 4-a] benzimidazole (III) in a good yield. Moreover, the amine (II) can be regenerated by treatment of III with 15% hydrochloric acid and its mechanism is speculated.