RESEARCH ON NITROGEN CONTAINING HETEROCYCLIC-COMPOUNDS .18. SYNTHESIS OF 9H-PYRROLO[2,1-C]-SYM-TRIAZOLO[4,3-A][1,4]BENZODIAZEPINE, A NOVEL TETRACYCLIC RING OF PHARMACEUTICAL INTEREST

Reaction of di-4-morpholinylphosphinic chloride on 5,10-dihydro-9H-pyrrolo[2,1-c][1,4]benzodiazepin-11-one 9 afforded 11-(di-4-morpholinylphosphinyloxy)-5H-pyrrolo[2,1-c][l,4]benzodiazepine 10. Displacement of di-4-morpholinylphosphinyloxy group of 10 by formylhydrazine with concomitant intramolecular cyclization led directly to 9H-pyrrolo[2,1-c]-s-triazolo[4,3-a][l,4]benzodiazepine 7, a novel nitrogen heterocyclic ring of pharmaceutical interest. A new procedure for the synthesis of 9 is also described.