TY - JOUR
T1 - Trimethylbromosilane catalyzed trimethylsilylation of slowreacting hydroxy- and oxosteroids in gas chromatographic-mass spectrometric analysis
AU - Aringer, L.
AU - Eneroth, P.
AU - Gustafsson, J. Å
N1 - Funding Information:
We wish to thank the colleagues named in Materials and Methods for their generous supply of reference steroids which made this work possible. This work was supported by grants from the Swedish Medical Research Council (Project No. 13X-2520), from Magnus Bergvalls Stiftelse and from Carl-Bertel Nathhorsts Vetenskapliga Stiftelse. One of us (J.-A.G) is indebted to "Syskonen Wess4ns Stiftelse" for a fellowship.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1971
Y1 - 1971
N2 - The trimethylsilylation of different hydroxy- and oxosteroids has been studied using hexamethyldisilazane and trimethylbromosilane instead of trimethylchlorosilane as the catalyst. Steroids with hydroxyl groups in positions 3, 11, 17, 20 and 21 (e.g. α- and β-cortol), react to form persilylated derivatives in high yields in 24 hours at room temperature. Steroid ketones easily react to form enol trimethylsilyl ethers. Significant enolization of a 17-oxo-(dehydroepiandrosterone) and a 20-oxo- (pregnenolone) group occurred after 5 minutes, and within 30 minutes of an 11-oxo compound (3α,20β-dihydroxy-5β-pregnan-11-one). After 3 hours a complete enol trimethylsilylation was obtained with pregnenolone but not with dehydroepiandrosterone. No complete persilylation was obtained with 11-oxo- or 20-oxo-17α-hydroxy compounds within 24 hours. It is recommended that the trimethylbromosilane reagent is used after conventional trimethylsilylation of polyhydroxy steroids. It is advisable that 3- and 20-oxo-steroids are converted into O-methyloxime derivatives before persilylation is made with the trimethylbromosilane reagent.
AB - The trimethylsilylation of different hydroxy- and oxosteroids has been studied using hexamethyldisilazane and trimethylbromosilane instead of trimethylchlorosilane as the catalyst. Steroids with hydroxyl groups in positions 3, 11, 17, 20 and 21 (e.g. α- and β-cortol), react to form persilylated derivatives in high yields in 24 hours at room temperature. Steroid ketones easily react to form enol trimethylsilyl ethers. Significant enolization of a 17-oxo-(dehydroepiandrosterone) and a 20-oxo- (pregnenolone) group occurred after 5 minutes, and within 30 minutes of an 11-oxo compound (3α,20β-dihydroxy-5β-pregnan-11-one). After 3 hours a complete enol trimethylsilylation was obtained with pregnenolone but not with dehydroepiandrosterone. No complete persilylation was obtained with 11-oxo- or 20-oxo-17α-hydroxy compounds within 24 hours. It is recommended that the trimethylbromosilane reagent is used after conventional trimethylsilylation of polyhydroxy steroids. It is advisable that 3- and 20-oxo-steroids are converted into O-methyloxime derivatives before persilylation is made with the trimethylbromosilane reagent.
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U2 - 10.1016/S0039-128X(71)80142-3
DO - 10.1016/S0039-128X(71)80142-3
M3 - Article
C2 - 5551846
AN - SCOPUS:0015029530
SN - 0039-128X
VL - 17
SP - 377
EP - 398
JO - Steroids
JF - Steroids
IS - 1-5
ER -