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Mass spectrometric study on methyl 5‐methyl‐2‐oxo‐3‐[2‐(4‐R‐phenyl)‐1‐ethyl]cyclopentanecarboxylates and methyl 2‐oxo‐5‐(4‐R‐phenyl)‐3‐propylcyclopentanecarboxylates
Author(s) -
He Xiaoran,
Chen Bei,
Wang Jianbo,
He Meiyu
Publication year - 1997
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/(sici)1097-0231(19971030)11:16<1818::aid-rcm992>3.0.co;2-q
Subject(s) - chemistry , substituent , methyl group , steric effects , deuterium , fragmentation (computing) , mass spectrometry , medicinal chemistry , electron ionization , phenyl group , methyl radical , methanol , ion , stereochemistry , radical , group (periodic table) , organic chemistry , alkyl , chromatography , physics , halogen , quantum mechanics , computer science , ionization , operating system
The mechanisms of mass spectrometric fragmentation of eight new compounds, including methyl 5‐methyl‐2‐oxo‐3‐[2‐(4‐R‐phenyl)‐1‐ethyl]cyclopentanecarboxylates (Group I, R = substituent) and methyl 2‐oxo‐5‐(4‐R‐phenyl)‐3‐propylcyclopentanecarboxylates (Group II, R = substituent), were studied using mass analyzed ion kinetic energy spectrometry. The chemical compositions of these compounds and some of their important fragment ions were verified by high‐resolution MS data. There were two types of H‐rearrangement as regards the route of fission. In one type, the γ‐H migration was influenced by both the electron effect and the steric hindrance of substituents, whereas on the other α‐H migration losing methanol was due to the α‐position active hydrogen located between two carbonyls, and this was verified by the method of deuterium labelling. © 1997 John Wiley & Sons, Ltd.