Mass spectrometric intramolecular cyclization reactions of some 2‐N‐phenyliminoperhydro‐1,3‐oxazines

Pirjo Vainiotalo, F. Fülöp, G. Bernáth, Kalevi Pihlaja

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Mass spectrometric fragmentation of four monocyclic and eight condensed skeleton 2‐N‐phenyliminoper‐hydro‐1,3‐oxazine derivatives have been characterized by metastable ion analysis, collision induced dissociation measurements, exact mass measurements and ion structural studies. Extensive rearrangement reactions, best characterized in terms of intramolecular cyclizations, took place. Namely, when R = H the N‐cyclization was almost exclusive whereas in cases where R > H steric reasons rendered the O‐cyclization more feasible. Part of the fragmentation of the R = H compounds seemed to occur via the amino form. On the other hand the methane chemical ionization spectra of cis‐ and trans‐anellated 5,6‐trimethylene‐2‐N‐phenyliminoperhydro‐1,3‐oxazines proved that at least some imino structure was present in the gas phase.

Original languageEnglish
Pages (from-to)1453-1459
Number of pages7
JournalJournal of Heterocyclic Chemistry
Issue number5
Publication statusPublished - 1989


ASJC Scopus subject areas

  • Organic Chemistry

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