
%0 Journal Article
%A Dyall, LK 
%T Mass-Spectra of Annelated 4H-3,1-Oxazin-4-ones
%J Australian Journal of Chemistry
%D 1989/10/01
%V 42
%N 10
%P 1813-1818
%K 
%R https://doi.org/10.1071/CH9891813
%U https://www.publish.csiro.au/paper/CH9891813 
%X Electron-impact fragmentation of 2-R-4H-3,1-benzoxazin-4-ones involves primary losses of CO2 and R; there is also loss of ketene when R is methyl. The ion RCO+ is a major daughter. Successive losses of CO2and RCN yield an ion m/z 76 formulated as dehydrobenzene radical cation. In the case of 2-methyl-4H-3,1-naphth[2,3-d]oxazin-4-one, the 2,3-dehydronaphthalene ion is produced efficiently, and linked scans (B/E) were used to demonstrate that it loses C4H2 ( diacetylene ) in a retro Diels-Alder reaction. 
