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Radical processes in remote charge fragmentations of lithium‐cationized long‐chain alkenyl and alkadienyl salicylic acids
Author(s) -
Claeys M.,
Van den Heuvel H.
Publication year - 1994
Publication title -
biological mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1052-9306
DOI - 10.1002/bms.1200230105
Subject(s) - chemistry , allylic rearrangement , fragmentation (computing) , ion , homolysis , photochemistry , lithium (medication) , radical , hydrogen , dissociation (chemistry) , stereochemistry , medicinal chemistry , organic chemistry , catalysis , medicine , endocrinology , computer science , operating system
Multistep radical processes are proposed to rationalize the formation of product ions formed by collisionally induced and spontaneous fragmentation of lithium‐cationized 6‐alkenyl and 6‐alkadienyl salicylic acids. An important step in these processes consists of a homolytic CH cleavage, a mechanism which is consistent with the charge‐remote concept. Evidence is given by the observation that the fragmentation of ions formed by the loss of a hydrogen radical is similar to that found for the precursor [M − H + 2Li] + ions. The proposed mechanisms also explain very well the observed enhanced abundances of ions whose formation involves formal benzylic, homo‐benzylic and homoallylic cleavages. The enhanced abundance of ions whose formation involves formal allylic cleavages can be readily rationalized by resonance stabilization of intermediate allylic radical ions.