Electron impact studies. Part CIV. Cyclisation reactions of negative ions. The o-O2NC6H4(CHCH)nCOR system
- 1 January 1976
- journal article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 2
- No. 14,p. 1656-1659
- https://doi.org/10.1039/p29760001656
Abstract
Negative-ion mass spectra of compounds of the general type o-O2NC6H4(CHCH)nCOR (n= 1–3) show rearrangement peaks produced by novel cyclisation reactions occurring between the adjacent substituents. When n= 1. reactions proceed mainly through six- and seven-membered transition states, whereas for n= 2, six-centred states still predominate, but reactions also occur via five-membered transition states. Major fragment ions correspond to charged 1,2-dicarbonyl (n= 1), 2-ene-1,4-dicarbonyl (n= 2), and 2,4-diene-1,6-dicarbonyl (n= 3) systems. Rearrangement ions are not observed when the nitro-group is replaced by a carboxy-group.Keywords
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