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Electron impact and chemical ionization mass spectra of norbornane/ene di-exo and di-endo-fused 1,3-oxazin-2(1H)-ones and 1,3-oxazine-2(1H)-thiones

✍ Scribed by Tuula Partanen; Pirjo Vainiotalo; Géza Stájer; Gábor Bernáth; Kalevi Pihlaja

Publisher
John Wiley and Sons
Year
1990
Tongue
English
Weight
448 KB
Volume
25
Category
Article
ISSN
1076-5174

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✦ Synopsis

Mass spectral fragmentations of four norbornaneleoe di-em-and di-endo-fused 1,3-oxazin-2( lH)-ones and four 1,3-oxazine-2(1H)-thiones were examined by means of metastable ion analysis, the collision-induced dissociation technique and exact mass measurement. Under electron impact (EI) conditions all the saturated compounds gave rise to complicated fragmentations, including several rearrangements. For the unsaturated compounds, a retro-Diels-Alder (RDA) process was the most favoured fragmentation pathway, which took place with hydrogen rearrangement to yield RDA + H fragments. The EI mass spectra did not permit isomeric differentiation. Under chemical ionization conditions, stereochemical effects were more perceptible, but isomeric differentiation was still difficult.

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