Investigation of 4-(nitrophenylamino)pent-3-en-2-ones and 4-(nitrobenzylamino)pent-3-en-2-ones by electron ionization mass spectrometry. Observation of characteristic ortho effects

Eur. J. Mass Spectrom. 9, 465–471 (2003)
DOI: 10.1255/ejms.579

Investigation of 4-(nitrophenylamino)pent-3-en-2-ones and 4-(nitrobenzylamino)pent-3-en-2-ones by electron ionization mass spectrometry. Observation of characteristic ortho effects

Rafał Frański,^* Błażej Gierczyk, Piotr Fiedorow, Dariusz Chadyniak and Włodzimierz Urbaniak
Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland. E-mail: franski@main.amu.edu.pl

ABSTRACT:

The compounds 4-(phenylamino)pent-3-en-2-ones (1–3) and 4-(benzylamino)pent-3-en-2-ones (4–6) substituted with a nitro group on the aromatic ring were studied by electron ionisation mass spectrometry (EIMS). It was deduced that the compounds 1–3 are converted into the tautomeric 4- (arylimino)pentan-2-one during the EI process. Mass spectrometric decompositions of ortho-substituted derivatives (1 and 4) were found to be different from those observed for meta– and para-isomers. The fragmentation pathways are discussed on the basis of data from linked B/E and B²/E scans, mass-analysed ion kinetic energy (MIKE) spectra, accurate mass measurements and isotope labelling.

Keywords: 4-(nitrophenylamino)pent-3-en-2-ones, 4-(nitrobenzylamino)pent-3-en-2-ones, tautomerisation, electron ionisation, fragmentation pathway, ortho effect

You can buy this paper on-line in PDF format; it costs only £11.75. Just click on the BUY on-line button. You can pay on-line through a secure server and get access immediately.