Synthesis of 5H-tetrazolo[5,1-c][1,4]benzodiazepines

A three step synthesis of 5H-tetrazolo5,1-c]1,4]benzodiazepin-11-ones 8a-d via the reaction of a substituted benzyl azide and ethyl cyanoformate is described. The derived lactams are converted to the corresponding 11-thiones 9a-d and, through the S-methylated derivatives, to the 11-amino analogs 11a-f. All of the described compounds are representatives of a novel ring system.