Alumina supported 12-tungstophosphoric acid as an efficient and reusable catalyst for synthesis of 1,5-benzodiazepines

Abstract

Alumina supported 12-tungstophosphoric acid catalyzes efficiently the reaction of o-phenylenediamine with ketones under solvent-free condition to afford the corresponding 1,5-benzodiazepines in good to excellent yields. The catalyst can be recovered and reused.