ELECTRON IMPACT STUDIES .29. C13H9 SKELETAL-REARRANGEMENT FRAGMENT IN MASS SPECTRA OF HETEROCYCLIC SYSTEMS CONTAINING DIPHENYL SUBSTITUENTS . A DEUTERIUM LABELLING STUDY

The m/e 165 ion (C13H9) has been noted in the mass spectra of a variety of heterocyclic systems containing two (or more) phenyl substituents. This skeletal-rearrangement fragment is most prominent in the spectra of particularly subsituted oxazoles, imidazoles, and thiazoles. Deuterium-labelling studies have allowed probable mechanistic formulations in the case of the 4,5-diphenylimidazoles, and the detection of two alternate rearrangement pathways in the spectrum of 2,4,5-triphenyloxazole. A comparison is made between the formation of m/e 165 in the spectrum of stilbene and 9,10-dihydrophenanthrene. © 1968.