Ultrasound assisted 1,4-diazabicyclo[2.2.2]octaniumdiacetate multicomponent synthesis of benzodiazepines: A novel, highly efficient and green protocol

Abstract

A simple and efficient method is presented for the synthesis of benzodiazepines through the multicomponent reaction of o-phenylenediamine, various aldehydes and 5,5-dimethylcyclohexane-1,3-dione (dimedone) in the presence of the acidic bis ionic liquid 1,4-diazabicyclo[2.2.2]octanium diacetate under ultrasound irradiation. The ionic liquid used is recoverable and reusable. This procedure is simple and environmentally friendly, and offers easy work-up, mild conditions and excellent yield in a short reaction time. All of the synthesized compounds were characterized by IR, ¹H NMR, mass spectrometry and elemental analysis.