Premium
The unimolecular fragmentation of steroidal amides under electron impact. The role of intermediary ion‐neutral complexes
Author(s) -
Longevialle Pierre,
And Guy Bouchoux,
Hoppilliard Yannik
Publication year - 1989
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.1210241013
Subject(s) - fragmentation (computing) , chemistry , amide , tautomer , ion , regioselectivity , computational chemistry , decomposition , electron ionization , hydrogen , stereochemistry , organic chemistry , computer science , catalysis , ionization , operating system
The neutral fragment produced in the main decomposition process of 3‐amido steroids after electron impact is shown, by thermochemical arguments, to have the amide structure rather than enolamide as would be expected from a simple McLafferty rearrangement. It is proposed that the enolamide to amide tautomerization takes place during the decomposition process involving ion‐neutral complexes, and is responsible for the lack of regioselectivity in the origin of the hydrogen transferred. An energy barrier of unknown origin is shown to exist in the formation of the accompanying [amide + H] + ion.