Bleile DM, Malmberg CE, Rowland AT. Steroid cyclicsulfites. III. Conformational and configurational aspects of steroid 3,5-cyclicsulfites.
Steroids 1975;
26:29-45. [PMID:
1166482 DOI:
10.1016/0039-128x(75)90004-5]
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Abstract
The reaction of 3beta, 5beta-dihydroxy cholestanes with thionyl chloride is shown to yield cyclicsulfite esters containing boat heterocyclic rings with the S=O oxygen axial or equatorial, depending upon the mode of formation. Treatment of a diol in pyridine at low temperature favors an equatorial S=O conformation while higher reaction temperatures in chloroform solution yield a mixture of axial and equatorial epimers. In the case of a 7alpha-bromo-6-oxo 3,5-sulfite, it has been shown that the S=O equatorial isomer may be converted to the axial isomer upon treatment with acid.
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