The process of retroâ1,3âdipolar cycloaddition of 2,5âdiarylâ1,3,4âdioxazoles induced by electronâimpact is discussed. For this purpose, 2âphenylâ5âpâchlorophenylâ1,3,4âdioxazole was prepared, labelled with18O in position 1; the spectrum of this compound showed clear evidence of retroâcycloaddition, 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. Copyright © 1974 Heyden & Son Ltd.
Mass spectrometry of heterocyclic compounds. VIâretroâ1,3âdipolar cycloaddition and competitive fragmentation reaction of 2,5âdiarylâ1,3,4âdioxazoles
SELVA CODDE', ALESSANDRO;Citterio, A.;
1974-01-01
Abstract
The process of retroâ1,3âdipolar cycloaddition of 2,5âdiarylâ1,3,4âdioxazoles induced by electronâimpact is discussed. For this purpose, 2âphenylâ5âpâchlorophenylâ1,3,4âdioxazole was prepared, labelled with18O in position 1; the spectrum of this compound showed clear evidence of retroâcycloaddition, 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. Copyright © 1974 Heyden & Son Ltd.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
