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Intramolecular hydrogen exchanges during the electron impact‐induced fragmentation of complex alicyclic amines
Author(s) -
Longevialle Pierre,
Marazano Christian
Publication year - 1976
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210110908
Subject(s) - alicyclic compound , fragmentation (computing) , chemistry , intramolecular force , electron ionization , hydrogen , deuterium , ion , molecule , mass spectrum , photochemistry , hydrogen bond , stereochemistry , organic chemistry , atomic physics , ionization , physics , computer science , operating system
The three‐step mechanism of formation of the important fragment ion of mass 84 from 3‐dimethylaminosteroids under electron impact is accompanied by intramolecular hydrogen exchanges, as shown by the mass spectra of deuterium labelled derivatives. The hydrogen exchanges are shown to occur in the ring A opened molecular ion, i.e. after the initial C‐3–‐C‐4 bond rupture, and to compete with the final C‐1–‐C‐10 bond rupture. (The intensity of hydrogen‐deuterium exchange reactions depends upon the activation energy of the final rupture.) The electron impact‐induced‐fragmentation of large alicyclic molecules bearing a strong charge stabilizing functional group, such as amines, appears to be the result of a series of displacements of the radical over different sites of the molecular ion through hydrogen (or carbon) rearrangements, with some of the radical sites being in the appropriate position to induce a final rupture.