Mass spectrometry of hydroxystilbazoles

The mass spectral fragmentation of the six 2′‐, 3′‐ and 4′ ‐hydroxy substituted 4‐ and 2‐azastilbenes is discussed and fragmentation pathways, elucidation of which were assisted by accurate mass measurements and metastable transitions, are proposed. It has been found that the position of the hydroxystyryl group in the pyridine ring may be deduced on the basis of mass spectral fragmentation patterns.