Solvent free synthesis of 1,5-benzodiazepines catalyzed by zirconium nitrate

Abstract

1,5-benzodiazepines are synthesized by the condensation of o-phenylenediamine and various ketones in the presence of Zr(NO₃)₄ under solvent free condition. The method offers mild reaction conditions, less reaction time, easy workup, high  yields, easy product isolation, selectivity of the reaction and reusability of catalyst.