Electron impact-induced fragmentation of 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones

The electron impact-induced fragmentations of 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones and some related compounds were investigated. On the basis of low- and high-resolution measurements, metastable ion studies by means of mass-analysed ion kinetic energy spectroscopy and collision-induced dissociation experiments, the main fragmentation pathways were established. The effect of methyl and phenyl substituents at the C(2) and C(3) positions of the heterocyclic ring on the fragmentations was also studied. The (1,3) ring splitting was investigated in some detail, using semi-empirical molecular orbital calculations.