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Mass spectra of 1,2‐alkylenedioxy‐substituted and related benzofurazans and benzofuroxans: differentiation between linear and angular isomers
Author(s) -
Takakis Ioannis M.,
Tsantali Georgia G.,
Haas George W.,
Giblin Daryl,
Gross Michael L.
Publication year - 1999
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199911)34:11<1137::aid-jms874>3.0.co;2-4
Subject(s) - chemistry , ion , spectral line , mass spectrum , ionization , abundance (ecology) , electron ionization , analytical chemistry (journal) , stereochemistry , organic chemistry , physics , astronomy , fishery , biology
The electron ionization (EI) mass spectra of [1,3]‐dioxolo‐, 6,7‐dihydro‐[1,4]‐dioxino‐, 7,8‐dihydro‐6 H ‐[1,4]dioxepino‐, 6,7,8,9‐tetrahydro[1,4]dioxocino‐, 7,8,9,10‐tetrahydro‐6 H ‐[1,4]dioxonino‐ and 6,7,8,9,10,11‐hexahydro[1,4]dioxecino[2,3‐ f ]‐2,1,3‐benzoxadiazoles (benzofurazans) and the corresponding 1‐oxides (benzofuroxans), all linear isomers, are reported. Also reported are the EI mass spectra of the corresponding angular isomers, [1,3]dioxolo‐, 7,8‐dihydro[1,4]dioxino‐, 8,9‐dihydro‐7 H ‐[1,4]dioxepino‐, 7,8,9,10‐tetrahydro[1,4]dioxocino‐, 8,9,10,11‐tetrahydro‐7 H ‐[1,4]dioxonino‐, 7,8,9,10,11,12‐hexahydro[1,4]dioxecino[2,3‐ e ]‐2,1,3‐benzoxadiazoles and the corresponding 1‐oxides. The relative abundance of the fragment ion of m/z 80 is characteristically enhanced in the spectra of the angular derivatives compared to the spectra of the linear counterparts. Collisionally activated decomposition studies show that it is structurally identical whether derived from the benzofurazans or the benzofuroxans. The relative abundance of the m/z 80 ion serves to distinguish between linear and angular isomeric pairs. In addition, the fragment ion at m/z 80 also serves to differentiate between the pairs of isomers, analogous to linear and angular, of six acyclic methoxy‐ and methoxymethyl‐substituted benzofurazans and their corresponding benzofuroxans. Copyright © 1999 John Wiley & Sons, Ltd.