Mass spectrometry of 3‐oxothiazolo[3,2‐ a ] and [3,2‐ c ]pyrimidin‐5‐ones. Correlation of the intensities of the M +. and the selected fragment ions

The mass spectral fragmentation of eight new 3‐oxothiazolo[3,2‐ a ] and [3,2‐ c ]pyrimidin‐5‐ones were investigated. Fragmentation pathways are proposed on the basis of accurate mass and metastable transition measurements. The correlation between the intensities of M +. and the selected fragment ions of these compounds is discussed. The data obtained created the basis for distinguishing isomers and metamers.