Studies in organic mass spectrometry. Part 27. Electron ionisation induced isomerisation of 3-aryl-4(3H)-quinazolinones

The comparison between 70 eV EI (electron ionisation) mass spectra, MIKE (mass analysed ion kinetic energy) and CID (collision induced dissociation) MIKE spectra, KER (kinetic energy release) and KERD (kinetic energy release distribution) data for 2-methyl-3-aryl-4(3H)-quinazolinones 1-4, with those of the corresponding 2-methyl-4-aryloxyquinazolines 1′-4′, indicates that aryloxy radical as well as hydrogen or methyl radical losses involve the formation of common intermediates. This suggests the occurrence of migrations of aryl groups from the N-3 atom to carboxylic oxygen in the molecular ions of 1-4.