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Gas chromatography mass spectrometry of trimethylsilyl ethers of sidechain hydroxylated Δ 4 ‐3‐ketosteroids. Long range trimethylsilyl group migration under electron impact
Author(s) -
Gaskell Simon J.,
Smith Andrew G.,
Brooks Charles J. W.
Publication year - 1975
Publication title -
biomedical mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0306-042X
DOI - 10.1002/bms.1200020309
Subject(s) - trimethylsilyl , chemistry , moiety , enol , electron ionization , mass spectrum , gas chromatography , labelling , ion , mass spectrometry , medicinal chemistry , stereochemistry , organic chemistry , chromatography , catalysis , biochemistry , ionization
The electron impact mass spectrum (70 eV) of 26‐trimethylsilyloxy‐4‐cholesten‐3‐one shows a base peak at m/e 196, attributable to combination of the trimethylsilyl group with a fragment of m/e 123 produced by cleavage across ring B . 18 O labelling confirms that the fragment of m/e 196 contains the 3‐oxygen atom, and 2 H labelling indicates retention of the trimethylsilyl moiety. Similar ions are observed from other Δ 4 ‐3‐ketones with sidechain trimethylsilyloxy groups: abundances depend on the site of substitution. The corresponding enol trimethylsilyl ethers are readily separable from the keto forms by gas‐liquid chromatography, and afford mass spectra in which the molecular ions are abundant, while ions of m/e 196 are of only moderate intensity.