Synthesis of imidazo[1,5-c][1,3]benzodiazepines via an Aza-Wittig/carbodiimide-mediated annulation process

Article abstract of DOI:10.1016/S0040-4020(97)10050-3

The first synthesis of the imidazo[1,5-c][1,3]benzodiazepine ring system has been carried cut by reaction of the iminophosphorane derived from the (Z)-5-(o-azidoarlylidene)hydantoin with isocyanates. The isomeric (E)-tributyliminophosphorane undergoes intramolecular aza Wittig reaction to give the imidazo[4,5-b]quinolin-2-one ring.