Optimization of the allylic oxidation in the synthesis of 7-keto-delta5-steroidal substrates

A variety of delta5-steroids were converted into alpha, beta-unsaturated 7-ketones using a modification of the already known method of t-butyl hydroperoxide in the presence of copper iodide in acetonitrile. The same alteration was applied to another oxidative procedure, which had never been used bef...

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Bibliographic Details
Published in:Steroids 2003-05, Vol.68 (5), p.407-414
Main Authors: Arsenou, Evaggelia S, Koutsourea, Anna I, Fousteris, Manolis A, Nikolaropoulos, Sotiris S
Format: Article
Language:English
Subjects:
Allyl Compounds - chemistry
Catalysis
Copper - chemistry
Iodides - chemistry
Ketosteroids - chemical synthesis
Molecular Structure
Oxidation-Reduction
tert-Butylhydroperoxide - chemistry
Time Factors
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Summary:A variety of delta5-steroids were converted into alpha, beta-unsaturated 7-ketones using a modification of the already known method of t-butyl hydroperoxide in the presence of copper iodide in acetonitrile. The same alteration was applied to another oxidative procedure, which had never been used before on steroidal substrates. The same oxidative agent was used in the presence of copper iodide, and tetra-n-butylammonium bromide was used as a phase-transfer catalyst in a two-phase system of water/methylene chloride. It was found that the allylic oxidation proceeded more efficiently when t-butyl hydroperoxide was added to the reaction mixture in portions. The initial addition of the total amount of oxidant or its dropwise addition afforded low yields. This observation contributes to the investigation of the reaction mechanism, and high-yield conversions of steroidal 5,6-enes into the corresponding conjugated 7-ones in short reaction times are reported.
ISSN:0039-128X