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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

✍ Scribed by Xiaoran He; Bei Chen; Jianbo Wang; Meiyu He

Publisher: John Wiley and Sons
Year: 1997
Tongue: English
Weight: 102 KB
Volume: 11
Category: Article
ISSN: 0951-4198
DOI: 10.1002/(sici)1097-0231(19971030)11:16<1818::aid-rcm992>3.0.co;2-q

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✦ Synopsis

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.

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