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Mass spectra of new substituted 2‐amino‐4 H ‐pyrans: a retro‐Diels‐Alder reaction pattern
Author(s) -
Lucas Ana de,
FernándezGadea Javier,
Martin Nazario,
Martínez Roberto,
Seoane Carlos
Publication year - 2000
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/1097-0231(20001015)14:19<1783::aid-rcm92>3.0.co;2-1
Subject(s) - chemistry , fragmentation (computing) , ketone , electrospray ionization , substituent , electron ionization , mass spectrum , collision induced dissociation , dissociation (chemistry) , chemical ionization , mass spectrometry , methyl vinyl ketone , ionization , amide , medicinal chemistry , photochemistry , stereochemistry , organic chemistry , tandem mass spectrometry , ion , chromatography , catalysis , operating system , computer science
New substituted 2‐amino‐3‐cyano‐4 H ‐pyrans have been studied by electron ionization (EI), chemical ionization (CI) and electrospray ionization (ESI) mass spectrometry. The retro‐Diels‐Alder reaction (RDA) is the main fragmentation pattern observed in the EI spectra forming an unsaturated ketone as the diene fragment. In contrast, a different RDA reaction takes place yielding an unsaturated amide as diene fragment together with the unsaturated ketone in the CI spectra. The MS/MS spectra obtained using an ESI source reveal that the favoured fragmentation by collision induced dissociation (CID) is the elimination of the substituent at the C4 position with formation of a stable pyrilium cation. Copyright © 2000 John Wiley & Sons, Ltd.