Synthesis of 1,5-Benzodiazepine derivatives catalysed by zinc chloride

2,3-Dihydro-1H-1,5-benzodiazepines have been synthesized by the condensation of o-phenylenediamine (OPDA) with cyclic or acyclic ketones in the presence of zinc chloride as catalyst at 80-85 °C. The yields are high and the reactions go to completion within 10-20 min. © 2006 The Japan Institute of Heterocyclic Chemistry