Synthesis of the novel pyrrolo[2,1-d][1,2,5]benzotriazepine, 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[1,2-a]quinoxaline via transamination of in situ generated 1-(2-aminophenyl)-2-iminomethylpyrroles

Article abstract of DOI:10.1016/0040-4020(96)00597-2

Selective reduction of 2-azidomethyl-1-(2-nitrophenyl)pyrrole 5 afforded 2-aminomethyl-1-(2-nitrophenyl)pyrrole 10. Pyrrolo[1,2-a]quinoxaline 15 is obtained by treating aminoester 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 with triphosgene or carbon disulfide yields pyrrolo[2,1-e][1,3,6]benzotriazocine 23 and 24, respectively. Intramolecular 1,3-dipolar cycloaddition of cyanoazide 6 gives pyrrolo[1,2-a]tetrazolo[1,5-d][1,4]benzodiazepine 25.