Fragmentation in doubly charged ion mass spectra of anhydropisatin and related compounds

Abstract The doubly charged ion mass spectra of anhydropisatin, 4‐methoxyanhydropisatin, 3, 8, 9‐trimethoxypterocarpen and 3, 4, 8, 9‐tetramethoxypterocarpen were determined, and the fragmentation was explained by assuming that the paired electrons were partially localized in the fragmentations and by comparing the spectra with that of 3‐(CD 3 )‐anhydropisatin. Conventional mass spectra of these compounds were very simple, but the doubly charged ion spectra were sufficiently characteristic for the reliable identification.