Dual mechanisms for the fragmentation of 1‐benzoylbenzotriazole upon electron impact

Abstract The electron impact induced fragmentation of 1‐benzoylbenzotriazole has been studied by 13C labelling experiments. It has been found that the loss of CO from the [M  N2]+˙ ions proceeds by two routes; about 78% of the ions decompose via the molecular ions of the corresponding thermal fragmentation product, 2‐phenylbenzoxazole, and 22% via those of the corresponding photochemical fragmentation product, 6‐phenanthridone.