Pyridine mass spectral peaks

Mass spectral data have been obtained for compounds (20), (21), (22), and (23). The data show that the most abundant peak for each is the molecular ion. Considerable amounts of (M — 1)+ and M+2 ions are also formed. Loss of HCN from the molecular ion is evidence for the pyridine ring, while loss of carbon monosulfide and/or the thioformyl radical are characteristic of the thiophene ring <75JHC865>. Mass spectral fragmentation patterns have also been reported for the halo- and halonitrothienopyridines (Scheme 3) <70AK(32)249,74JHC205). 

Some of the peak identifications given in Table 6.5.11 are tentative only. For example, the spectrum for 2-[3-(2-pyridyl)but-1-enyl]pyridine is not available in common mass spectral libraries. The tentatively assigned spectrum for this substance is shown in Figure 6.5.12. 

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