Electron-impact studies—LXIV: Negative-ion mass spectrometry of functional groups. Nitroaniline derivatives

The various fragmentations of the o-nitrobenzanilide molecular anion have been studied by labelling procedures and substituent effects. The loss of HO· from the molecular anion is a specific proximity effect, involving the oxygen of the nitro group and the hydrogen of the amide moiety. The losses of NO· from variously substituted nitrobenzenes are considered in depth and it is suggested that the nitro→ nitrite rearrangement is a radical reaction. Negative-ion mass spectrometry may be used for the structure determination of sulphonamides and nitrophenylhydrazones.