Document Detail

Energy-variable collision-induced dissociation study of 1,3,5-trisubstituted 2-pyrazolines by electrospray mass spectrometry.
MedLine Citation:
PMID:  17486690     Owner:  NLM     Status:  MEDLINE    
The pathways of the ([M+H](+)) ions generated from electrosprayed solutions of nine 1,3,5-trisubstituted 2-pyrazoline derivatives were studied using energy-variable collision-induced dissociation (CID) and pseudo-MS(3) (in-source CID combined with MS/MS) methods. It was shown that under CID conditions several structurally important product ions such as the 2,4-substituted azete and 1,2-substituted aziridine ions were formed. The compositions of the product ions were unambiguously supported by accurate mass measurement (mass accuracy was within +/- 8 ppm). The fragmentation pathways of 1,3,5-trisubstituted 2-pyrazolines were established by means of pseudo-MS(3). It was found that a substituent at the N-1 position greatly affects the fragmentation pathways of the 2-pyrazoline derivatives. The 1-acetyl- and 1-propionyl-2-pyrazoline derivatives dissociate mainly through formation of a pyrazolium cation, while in the case of 1-phenyl-2-pyrazoline derivatives product ions arising from the consecutive fragmentation of 2,4-substituted azete and 1,2-substituted aziridine ions dominate. Another interesting finding is the formation of a radical cation from the 2,4-substituted azete by loss of a methyl radical. The fragmentation yield as a function of the collision energy for each of the 1,3,5-trisubstituted 2-pyrazolines was determined. Based on the fragmentation yield versus collision energy curves the relative fragmentation stabilities for the 1,3,5-trisubstituted 2-pyrazoline derivatives were also evaluated.
Sándor Kéki; Lajos Nagy; János Török; Katalin Tóth; Albert Lévai; Miklós Zsuga
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Rapid communications in mass spectrometry : RCM     Volume:  21     ISSN:  0951-4198     ISO Abbreviation:  Rapid Commun. Mass Spectrom.     Publication Date:  2007  
Date Detail:
Created Date:  2007-05-17     Completed Date:  2007-07-16     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8802365     Medline TA:  Rapid Commun Mass Spectrom     Country:  England    
Other Details:
Languages:  eng     Pagination:  1799-808     Citation Subset:  IM    
Department of Applied Chemistry, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary.
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MeSH Terms
Indicators and Reagents
Magnetic Resonance Spectroscopy
Pyrazoles / analysis*
Spectrometry, Mass, Electrospray Ionization
Spectroscopy, Fourier Transform Infrared
Reg. No./Substance:
0/Indicators and Reagents; 0/Pyrazoles

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