Convenient Synthesis of Stigmasta-5, 25-dien-3β-ol and Stigmasta-5, 24 (25) -dien-3β-ol from Sitosterol

A method was developed for the synthesis of stigmasta-5, 25-dien-3β-ol from sitosterol, with the direct hydroxylation of the sitosterol side chain with methyl (trifluoromethyl) dioxirane and dehydration of the 25-hydroxylated compound with phosphorus oxychloride as key steps. Stigmasta-5, 25-dien-3β-ol and stigmasta-5, 24 (25) -dien-3β-ol were easily prepared from sitosterol and each was isolated by HPLC using a reversed-phase column.