Synthesis of 3‐Carboxylic derivatives of 1,5‐benzodiazepines

A series of 3‐carboxylic derivatives of disubstituted 1,5‐benzodiazepines (5–9) was synthesized by hetero‐cyclisation from 1,2‐diaminobenzene (1) with dibenzoylmethane (2) followed by bromination on position 3 and by introduction of the carboxylic group or introduction of the malonic moiety. Reduction of the hetero‐cycle gave the perhydro derivative diethyl (2,4‐diphenyl‐1,2,4,5‐tetrahydro‐3H‐1,5‐benzodiazepin‐3‐yl)malonate (9) .