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Hydrogen migration in the electron impact induced retro diels‐alder fragmentation of N ‐aryl‐4 H ‐5,7a‐epoxyisoindolines
Author(s) -
Mintas M.,
Klepo Ž.,
Jakopčić K.,
Klasinc L.
Publication year - 1979
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.1210140505
Subject(s) - fragmentation (computing) , aryl , chemistry , deuterium , mass spectrum , hydrogen , electron ionization , ion , medicinal chemistry , stereochemistry , photochemistry , organic chemistry , physics , atomic physics , alkyl , computer science , ionization , operating system
The electron impact induced fragmentations of the C‐5 unsubstituted and 5‐methyl N ‐aryl‐4 H ‐5,7a‐epoxyisoindolines (where aryl is pheny, p ‐tolyl, p ‐methoxyphenyl, o ‐methoxyphenyl and p ‐chlorophenyl) were investigated. The fragmentation patterns deduced were supported by exact mass measurements of prominent ions and by deuterium labelling. The retro Diels‐Alder fragmentation turned out to be a predominant process in all the compounds investigated. In the mass spectra of the 5‐methyl N ‐aryl‐4 H ‐5,7a‐epoxyisoindolines hydrogen migration preceding fragmentation occurred. From the mass spectrum of the specifically deuterated compound it was concluded that the transferred hydrogen originates exclusively from the 5‐methyl group.