Zur Massenspektrometrie von Nitrophenylverbindungen—I. Nitrophenylphydrazone Aromatischer Aldehyde und Ketone und Verweandte Verbindungen

Abstract

Fragmentation under electron impact of phenylhydrazones of aromatic aldehydes and ketones, of nitrostilbenes, nitrobenzalacetophenones and analogous compounds is determined by intramolecular oxidation reactions. Oxygen transfer from the o-nitrogroup on to the hydrazon-or stilbene-double bond is taking place; degradation of the resulting rearrangement products provides some of the most characteristic features in the mass spectra of such compounds. The spectra of 20 out of 40 compounds investigated are presented and discussed. Several other rearrangement reactions are observed. An additional conjugated double bond in the hydrawne chain completely changes the reactivity under electron impact. Even saturated substituents (cyclopropyl) can be drastically affected in their mode of fragmentation by an o-substituted nitrogroup.

Campholenic aldehyde ozonolysis: a mechanism leading to specific biogenic secondary organic aerosol constituents

“…The formation of deprotonated terpenylic acid represents a quite unusual behaviour and might be explained by an intramolecular transfer of oxygen from the nitro group. The migration of an oxygen atom from the ortho nitro group to the -CH=N-substructure, followed by rearrangements, has been known for long from hydrazones and was described for derivatised aromatic and aliphatic aldehydes and ketones (Djerassi and Sample, 1965;Goldsmith and Djerassi, 1966;Kleipool and Heins, 1964;Seibl, 1970;Seibl and Völlmin, 1968). Based on the observed fragmentation in the present study, the m / z 335 was assigned as the DNPH derivative of terpenylic aldehyde.…”

Chemical ionization mass spectra of 2,4-dinitrophenylhydrazones of carbonyl and hydroxycarbonyl atmospheric pollutants

“…However, little information is available concerning the mass spectra of carbonyl DNPH. Only a few studies have described DNPH fragmentation under electron impact (El) (10)(11)(12), and the chemical ionization (Cl) mass spectra of these compounds have apparently not been studied. The extensive fragmentation of DNPH under electron impact makes it difficult to use the El mass spectra of DNPH for identification of trace levels of carbonyls in complex mixtures.…”

Mass spectrometry of nitroazoles: 4—ortho effects: The loss of CHO˙ and CH2O from methyl substituted nitrodiazoles

“…While the above-mentioned isomers are examples of compounds meeting either condition (2) or (3) and of course the first condition, l-methyl-5-nitropyrazole (2) does have both a N-bonded methyl group and a second heteroatom in an adjacent position. The azole nitrogen can act as a hydrogen acceptor, initiating a reaction mechanism which has some similarities with the fragmentation sequence given for compounds in group I (Scheme 3).…”