Mass spectra of 4,5-disubstituted 1,2,3-thiadiazoles

The schemes of the fragmentation of 4-substituted 5-arylamino-1,2,3-thiadiazoles were established on the basis of electron-impact mass spectra and high-resolution mass-spectrometric data, and the effect of substituents on the fragmentation pathways was analyzed. It is shown that the cyclization of the [M-N₂]⁺ ions formed in the fragmentation of compounds that contain a thiocarboxamido group in the 4 position proceeds with the participation of the most nucleophilic heteroatom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 118–122, January, 1988.