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Mass spectrometric intramolecular cyclization reactions of some 2‐ N ‐phenyliminoperhydro‐1,3‐oxazines
Author(s) -
Vainiotalo Pirjo,
Fülöp Ferenc,
Bernáth GÁBor,
Pihlaja Kalevi
Publication year - 1989
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570260540
Subject(s) - chemistry , fragmentation (computing) , intramolecular force , oxazines , steric effects , mass spectrum , ion , dissociation (chemistry) , mass spectrometry , medicinal chemistry , collision induced dissociation , ionization , stereochemistry , computational chemistry , photochemistry , tandem mass spectrometry , organic chemistry , chromatography , computer science , operating system
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.