Electron ionization fragmentations of some N‐substituted 2‐N‐methylimino‐4,5‐tetramethyleneperhydro‐3, 1‐oxazines and related thiazines

Kalevi Pihlaja, Sirpa Liukko‐Sipi, Ference Fülöp, G. Bernáth, Prijo Vainiotalo

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The 70 eV electron ionization mass spectra of six cyclohexane fused 2‐N‐methyliminoperhydro‐3,1‐oxazines and six related thiazines were recorded and their fragmentation behaviour studied by metastable‐ion analysis and exact mass measurement. For the unsubstituted compounds, decompositions which can be rationalized to start as a simple α‐cleavages with respect to the ring nitrogen atom were dominant. Many of these reactions were accompanied by a hydrogen‐atom transfer to the neutral fragment lost. N‐substitution prompted more extensive hydrogen migrations to take place, where hydrogen atoms were transferred to the heterocyclic part of the molecule. Only methyl‐substituted compounds showed remarkable sterochemical specificity, thus allowing isomeric differentiation to take place.

Original languageEnglish
Pages (from-to)230-233
Number of pages4
JournalRapid Communications in Mass Spectrometry
Issue number5
Publication statusPublished - 1991


ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry

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