Mass spectra of benzoxazolone derivatives

N-Acetonylbenzoxazolones containing a substituent in the acetonyl residue, as well as their hydrazones and oximes, decompose under the influence of electron impact to give primarily fragments of N-methylene- or N-methylbenzoxazolones. For the oximes and hydrazones the characteristic ions are (M -OH) and (M — NH₂), which evidently have cyclic structures. The isomeric aryl triazinones undergo fragmentation via the scheme of the retrodiene synthesis. The characteristic ions that make it possible to distinguish the isomeric benzoxazolones, arylimidazolones, and aryltriazinones were found.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1493–1497, November, 1976.