The loss of SO 2 H from an imido‐sulfite under electron impact: Structural elucidation by collision activation of the resulting fragment

Electron impact mass spectrometry of an imido‐sulfite 5,6‐benzo‐2‐imino‐ N ‐(2,4,6‐trichlorophenyl)‐1,3‐dioxa‐2‐thiacycloheptane shows an intense fragment ion corresponding to the expulsion of SO 2 H from the molecular ion. A mechanism that requires a rearrangement of the molecular ion is proposed. Structural elucidation of the [MSO 2 H] + ion was obtained by recording its metastable ion and collisional activation spectra. Comparison of these spectra with similar spectra recorded from a precursor ion of known structure demonstrated that they were identical. Thus, the results support the proposed structure which derives from the expulsion of SO 2 H from the molecular ion of the compound 5,6‐benzo‐2‐imino‐ N ‐(2,4,6‐trichlorophenyl)‐1,3‐dioxa‐2‐thiacycloheptane.