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Electron‐impact induced fragmentation of some natural products containing bis‐2,2‐dimethylchromene and bis‐2,2‐dimethylchroman ring systems
Author(s) -
Duffield A. M.
Publication year - 1969
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.1210021005
Subject(s) - fragmentation (computing) , electron ionization , chemistry , mass spectrum , ion , polyatomic ion , ring (chemistry) , metastability , deuterium , yield (engineering) , medicinal chemistry , stereochemistry , crystallography , organic chemistry , materials science , atomic physics , physics , computer science , metallurgy , ionization , operating system
Derivatives of eriostoic and eriostemoic acids (II and III) and their tetrahydro analogs (VI and IX) which contain the bis‐2,2‐dimethylchromene and the bis‐2,2‐dimethylchroman ring systems respectively, fragment subsequent to electron‐impact in characteristic fashion. The former yield mass spectra dominated by the loss of a methyl radical from their molecular ions while the latter exhibit preferential fragmentation of the heterocyclic ring system. In particular the hydrogen transfer process accompanying elemination of C 4 H 7 from the parent ion of bis‐2,2‐dimethylchromans was investigated by deuterium labeling studies. Fragment ions containing the bis‐2,2‐dimethylchroman ring undergo further fragmentation by the loss of C 4 H 8 rather than C 4 H 7 . An unusual elimination of CH 5 (accompanied by the appropriate metastable ion) from the molecular ions of the 3,5‐dinitrobenzoate esters (XIV and XV) was observed in their mass spectra.