Functionalisation of Non-Activated Positions in Steroids

[摘要] The work described in this thesis attempted to introduce functionality into non-activated positions in readily available steroids. Section 3. 1 describes the ceric ammonium nitrate (CAN) oxidation of 25-hydroxy-5alpha-lanost-8-en-3beta-yl acetate. Oxidation mainly occurs at the allylic positions and this was confirmed by the CAN oxidation of 5alpha-lanost-8-en-3beta-yl acetate. An interesting nitrogenous compound was produced in which the starting material incorporated the solvent acetonitrile. CAN oxidation of 24(R,S)-hydroxy-5alpha-cholestan-3beta-yl acetate gave only dehydration products. Section 3.4 describes the functionalisation of the C-30 methyl group in 7alpha-hydroxy-5alpha-lanostan-3beta-yl acetate using various reagents. Long range functionalisation, using radical relay chlorinations developed by Breslow, was attempted on the bile acid derivative, 3-pyridylmethyl 3alpha-acetoxy-5beta-cholan-24-oate. Chlorination mainly occurred at the C-14 tertiary position. CrO3 oxidations of 5alpha-androstan-3beta-yl acetate and 5alpha-cholestan-3beta-yl acetate were performed in order to compare the selectivity of the oxidations. 5alpha-Cholestan-3beta-yl acetate produced degraded steroids whereas 5alpha-androstan-3beta-yl acetate gave the reported Delta14-16-ketone as the major product.

[发布机构] University:University of Glasgow

[关键词] Analytical chemistry