PICTET-SPENGLER REACTION IN TRIFLUOROACETIC-ACID - LARGE-SCALE SYNTHESIS OF PYRIDOINDOLOBENZODIAZEPINE AS AN ATYPICAL ANTIPSYCHOTIC AGENT

Traditional syntheses of benzodiazepines involve a Bischler-Napieralski reaction which is a three step process and gives low overall yields. An attractive alternative is to construct the diazepine ring under Pictet-Spengler conditions. This paper reports the synthesis of a novel pyridoindolo-benzodiazepine as a potent atypical antipsychotic agent. The key step in the synthesis is the ring formation of the diazepine ring in neat trifluoroacetic acid.