SYNTHESIS OF THE NOVEL PYRROLO[2,1-D][1,2,5]BERAZOTRIAZEPINE, PYRROLO[2,1-E][1,3,6]BENZOTRIAZOCINE AND PYRROLO[1,2-A]TETRAZOLO[1,5-D][1,4]BENZODIAZEPINE RING-SYSTEMS - A NEW ROUTE TO PYRROLO[1,2A]QUINOXALINE VIA TRANSAMINATION OF IN-SITU GENERATED 1-(2-AMINOPHENYL)-2-IMINOMETHYLPYRROLES

Selective reduction of 2-azidomethyl-1-(2-nitrophenyl)pyrrole 5 afford ed 2-aminomethyl-1-(2-nitrophenyl)pyrrole 10. Pyrrolo[1,2-a]quinoxalin e 15 is obtained by treating amino-ester 12 with formaldehyde. Diamine 8 reacts with either formaldehyde or benzaldehyde to give pyrrolo[1,2 -a]quinoxaline 19. Compound 10 was reductively cyclised to pyrrolo[2,1 -d][1,2,5]-benzotriazepine 22. Intramolecular coupling of diamine 8 wi th triphosgene or carbon disulfide yields pyrrolo[2,1-e][1,3,6]benzotr iazocine 23 and 24, respectively. Intramolecular 1,3-dipolar cycloaddi tion of cyanoazide 6 gives pyrrolo[1,2-a]tetrazolo[1,5-d][1,4]benzodia zepine 25. Copyright (C) 1996 Elsevier Science Ltd