A very short degradation of the bile acid side chain
作者:Derek H. R. Barton、Jocelyne Wozniak、Samir Z. Zard
DOI:10.1039/c39870001383
日期:——
Reaction of the cholanic acid derivative (1) with thionyl chloride and pyridine gave, after quenching with methanol, the α-sulphine ester (3); treatment with acetic anhydride–sulphuric acid afforded the keto ester (5) which, on exposure to air in the presence of copper(II) ions and base, gave the 20-keto pregnane derivative (9) in excellent overall yield.
A short and efficient degradation of the bile acid side chain. Some novel reactions of sulphines and α-ketoesters
作者:Derek H.R. Barton、Jocelyne Wozniak、Samir Z. Zard
DOI:10.1016/s0040-4020(01)89235-8
日期:1989.1
with thionyl chloride and pyridine followed by addition of methanol. The sulphine group can be cleaved to the 23-ketone 9 in high yield using a variety of oxidising agents such as ozone, sodium hypochlorite, hydrogen peroxide or dinitrogentetroxide or alternatively by exposure to acetic anhydride-sulphuric acid. With dinitrogentetroxide, the reaction can be stopped at the oxime 10 stage. Finally aerial