1,3,4‐Benzotriazepinones. Formation and rearrangement

Anthranilic hydrazide reacts with orthoesters to produce mixtures of 3 products: 3,4‐dihyro‐5H‐1,3,4‐benzotriazepin‐5‐ones (1), 3‐amino‐3,4‐dihydro‐4‐quinazolinones (2) and 2‐(2‐aminophenyl)‐1,3,4‐oxadiazoles (4). The origin of these materials has been investigated. Product distributions depend on the nature of substituents, solvent and time. In ethanol benzotriazepinones are kinetically favored, but formed reversibly they subsequently rearrange to 2 and 4. Aminoquinazolinone formation is suppressed in aprotic solvents at moderate temperatures. Earlier failures to obtain 1 are due to its tendency to isomerize. Acid, base and thermal rearrangements have been observed. Mechanisms are proposed for the formation of 1, 2 and 4, and for the rearrangements of the benzotriazepinones. Pyrazolo‐ and imidazotriazepinones have been prepared from the corresponding o‐aminoazole hydrazides.