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A novel fragmentation of trimethylsilyl ethers of 3β‐hydroxy‐Δ 5 ‐steroids
Author(s) -
Björkhem Ingemar,
Gustafsson JanÅrke,
Sjövall Jan
Publication year - 1973
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210070305
Subject(s) - fragmentation (computing) , trimethylsilyl , chemistry , mass spectrum , polyatomic ion , ether , hydrogen , ion , medicinal chemistry , oxygen atom , oxygen , stereochemistry , molecule , organic chemistry , computer science , operating system
An ion formed by loss of 56 mass units from the molecular ion is often seen in mass spectra of trimethylsilyl ethers of C 19 and C 21 steroids having a 3β‐hydroxy‐Δ 5 structure and an oxo group at C‐17 or C‐20. The nature of this fragment was investigated by the use of perdeuteriotrimethylsilyl ether derivatives and of [4‐ 14 C], [3‐ 18 O], [4,4‐ 2 H 2 ] and [2,2,4,4‐ 2 H] labelled derivatives of 3β‐hydroxy‐5‐androsten‐17‐one and 3β‐hydroxy‐5‐pregnen‐20‐one. Evidence is presented to show that the neutral fragment of mass 56 is composed of carbon atoms 1, 2 and 3, the oxygen at C‐3 and four hydrogen atoms. During the fragmentation process, the trimethylsilyl group and one of the hydrogens at C‐2 are transferred to the fragment that carries the charge.