Electron ionization mass spectra of aryl- and benzyl-substituted 2,3-dihydroimidazo[1,2-a]pyrimidine-5,7(1H,6H)-diones.
The electron ionization mass spectra of the 1-phenyl-, 1-benzyl- and 6-benzyl-1-phenyl-2,3-dihydroimidazo[1,2-a]pyrimidine-5,7(1H,6H)-dione derivatives were recorded at 70 eV to find out the effects of substituents on their fragmentations. Fragmentation pathways were studied using B/E and B(2)/E scans. Some fragmentations involved the loss of C(3)HO(2) or carbon suboxide. The possibility of keto-enol tautomerism was also studied. For comparison selected compounds were studied using (1)H and (13)C NMR spectroscopy to reveal the presence of possible tautomerism. Some ions including [M-OH](+) and [M-HCO](+) and NMR results indicate that the enol form is predominant both in the gas and in the liquid phase.
Martiskainen
Olli
O
Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
Kivelä
Henri
H
Matosiuk
Dariusz
D
Szacon
Elzbieta
E
Rzadkowska
Marzena
M
Pihlaja
Kalevi
K
D007477:Ions; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011743:Pyrimidines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D007477:Ions; D011743:Pyrimidines