Premium
OH˙ loss and molecular rearrangements of quinoxaline N ‐oxides studied by interpretation of mass spectra and application of linear discriminant analysis
Author(s) -
Bartoszek M.,
Salzwedel D.,
Stumm G.,
Niclas H.J.
Publication year - 1987
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210220507
Subject(s) - quinoxaline , chemistry , linear discriminant analysis , molecule , mass spectrum , fragmentation (computing) , mass spectrometry , stereochemistry , mathematics , organic chemistry , chromatography , statistics , biology , ecology
Quinoxaline N ‐oxides substituted at the ortho position to the NO group give characteristic [M – OH] + fragments. With the di‐N‐oxides the peak intensities depend on the electron‐withdrawing strength of the 2‐ and 3‐substituents. Linear discriminant analysis was used to study the fragmentation of quinoxaline N ‐oxides as determined by the number of NO groups. Results of peak selection and discriminant analysis (Fisher quotients and discriminant vector coefficients) were interpreted with regard to the mass spectrometric decomposition of quinoxaline and quinoxaline N ‐oxide molecules. For the substituted quinoxaline TV‐oxides, fragmentations involving molecular rearrangements like those observed for unsubstituted quinoxaline N ‐oxidles were also found. For these compounds, partial rearrangement to quinoxalinones is confirmed.