Fragmentation sous l'impact electronique d'imidazo[1,5-b]triazepinones-1,2,4 et d'imidazo[4,5-b]pyridinones

The mass spectra of 1,2,4-imidazo[1,5-b]triazepinones and imidazo[4,5-b]pyridinones, formed by condensation of diaminoimidazoles with β-dicarbonyl compounds, are reported and analysed. The main fragmentation pathways have been determined and the utility is shown in structure determinations of isomeric compounds.