Premium
Mass spectrometry of heterocyclic compounds. VI —retro‐1,3‐dipolar cycloaddition and competitive fragmentation reaction of 2,5‐diaryl‐1,3,4‐dioxazoles
Author(s) -
Selva A.,
Citterio A.,
Pella E.,
Tonani R.
Publication year - 1974
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.1210091008
Subject(s) - cycloaddition , fragmentation (computing) , chemistry , metastability , ion , 1,3 dipolar cycloaddition , mass spectrum , mass spectrometry , ring (chemistry) , dipole , cleavage (geology) , computational chemistry , electron ionization , stereochemistry , medicinal chemistry , organic chemistry , materials science , chromatography , composite material , fracture (geology) , computer science , catalysis , ionization , operating system
Abstract The process of retro‐1,3‐dipolar cycloaddition of 2,5‐diaryl‐1,3,4‐dioxazoles induced by electron‐impact is discussed. For this purpose, 2‐phenyl‐5‐ p ‐chlorophenyl‐1,3,4‐dioxazole was prepared, labelled with 18 O in position 1; the spectrum of this compound showed clear evidence of retro‐cycloaddition, the dipole fragment retaining the positive charge. This labelled compound also provides a reliable interpretation of other cleavage modes of the heterocyclic ring. The elemental compositions of the ions considered were determined by exact mass measurements and the metastable transitions were detected through the defocusing technique of the electrostatic sector.