Thiazoles mass-spectrometric fragmentation

The electron impact mass spectra of a series of selenazoles have been compared with those of their thiazole analogs. The results indicate that, in general, the mass spectrometric fragmentation patterns of the selenium heterocycles can be predicted by an examination of the corresponding sulfur analog. One of the characteristics of the mass spectra of selenium compounds is that they are rich in ions due to the presence of the six relatively abundant stable selenium isotopes (81JHC1335). 

The first mass spectrometric investigation of the thiazole ring was done by Clarke et al. (271). Shortly after, Cooks et al., in a study devoted to bicydic aromatic systems, demonstrated the influence of the benzo ring in benzothiazole (272). Since this time, many studies have been devoted to the influence of various types of substitution upon fragmentation schemes and rearrangements, in the case of alkylthiazoles by Buttery (273) arylthiazoles by Aune et al. (276), Rix et al. (277), Khnulnitskii et al. (278) functional derivatives by Salmona el al. (279) and Entenmann (280) and thiazoles isotopically labeled with deuterium and C by Bojesen et al. (113). More recently, Witzhum et al. have detected the presence of simple derivatives of thiazole in food aromas by mass spectrometry (281). 

The first mass spectrometric study of thiazoles was carried out by Clark et al. (115), who investigated the method of fragmentation of thiazole, and 4-methyl- and 2,4-dimethylthiazole. 

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