Diazo-, azo-, and azidoazoles. VII. Imidazo[1,2-b]- versus imidazo[2,1-c]benzo-as-triazines

Treatment of 3-aminobenzo-as-triazines with bromoacetaldehyde ethylene acetal give linear tricyclic imidazobenzo-as-triazines, where 3-amino-7-methylbenzo-as-triazine 1-oxide yields the angular isomer. The structures of these compounds have been established by comparing their nmr spectra to those of pyrazolo 5,1-c]- and s-triazolo5,1-c]benzo-as-triazines obtained form the appropriate azo derivatives by intramolecular cyclization.