Preyssler Catalyst-Promoted Rapid, Clean, and Efficient Condensation Reactions for 3H-1,5-Benzodiazepine Synthesis in Solvent-Free Conditions.

A simple, convenient, and environmentally benign synthesis of 1,5-benzodiazepines is developed by condensing different o-phenylenediamines and 1,3-aryl-1,3-propanodiones.