THE STEREOCHEMISTRY OF THE SIDE CHAIN OF PHYTOSTEROL——AN ATTEMPT AT SYNTHESIS OF 24-ISO-β-SITOSTEROL
HUANG Wei-Yuan; HSU Jin-Wen; SUN Shie-Cherng Institute of Organic Chemistry, Academia Sinica
In order to determine the configuration at C_(20) of γ-sitosterol by the conventional chemical method of correlation of configuration, a synthesis of 24-ethyl cholesterol using hyodesoxycholic acid (IV) as the starting material has been carried out. The series of reactions involved is as follows: IV → Va → Vb → Vc → Vd → VIc → VIf → VIII → VIg → VIh → VIi → 24-cthyl cholesterol. However, the final product was found to be β-sitosterol instead of the expected 24-iso-β-sitosterol.