Synthesis, characterization and electron impact mass spectrometry of Schiff bases rearranging to oxazoline, thiazoline and thiazole derivatives

A series of oxazoline compounds have been prepared by reaction of 2,6‐diformyl‐4‐chlorophenol, 2,6‐diformylpyridine or 2,5‐diformylthiophen with o‐aminophenol or o‐aminothiophenol respectively. The oxazoline derivatives are stable both in solid state and in solution while the thiazoline derivatives easily oxidize to the corresponding thiazoles. Physico‐chemical data confirm this oxidation process. The 70 eV electron impact induced decomposition pathways of these compounds, obtained with the aid of exact mass measurements, B/E linked scans and collisional spectroscopy, are discussed in detail.