Mass spectra of imidazo[2,1-b]thiazole and thiazolo[3,2-f]xanthene derivatives

The general principles of the mass-spectrometric disintegration of imidazo [2,1-b]thiazole and thiazolo[3,2-f]xanthene derivatives were established, and the characteristic fragments were identified. Disintegration proceeding with cleavage of the bonds in the thiazole ring of the 2(3)-ring system is characteristic of all of the investigated compounds. The cleavage of the S-C bonds, which are the weakest in the investigated systems, proceeds especially readily. Intense peaks of ions due to stepwise disintegration of the pyrimidine ring are also observed in the spectra of thiazoloxanthenes.