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The electron impact induced cleavage of the C‐17—C‐20 bond and D‐ring in trimethylsilyl derivatives of C 21 steroids. Reciprocal exchange of trimethylsilyl groups
Author(s) -
Vouros Paul,
Harvey D. J.
Publication year - 1980
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.1200070508
Subject(s) - trimethylsilyl , chemistry , cleavage (geology) , silylation , medicinal chemistry , fragmentation (computing) , ring (chemistry) , stereochemistry , bond cleavage , photochemistry , organic chemistry , catalysis , materials science , fracture (geology) , computer science , composite material , operating system
The cleavage of the C‐17–C‐20 bond in the trimethylsilyl derivatives of C 21 steroids has been investigated with the aid of isotopic labelling. A significant amount of reciprocal exchange was observed between trimethylsilyl groups or hydrogen atoms on the 20‐O‐ and 17‐O‐positions. The loss of positional identity of these groups was found to influence the specificity of fragmentation reactions associated with the 17β‐sidechain and the D‐ring. It is supposed that the interchange of these silyl groups is facilitated by donation of the non‐bonding electrons on oxygen to the empty d orbitals of silicon.