The synthesis of cholesterol-25-3H (9) described here starts with the readily available 3β-hydroxy-δ5-cholenic acid (1). The acetate of this acid was converted to the next higher homolog by the Arndt-Eistert method. Grignard reaction with methyl iodide gave 25-hydroxycholesterol (6), which was then brominated. Tritium was finally introduced by treating the 25-bromocholesterol (8) with LiAl3H4.
                                    这里介绍的
胆固醇-25-3H(9)的合成是从现成的 3β-hydroxy-δ5-cholenic acid(1)开始的。通过 Arndt-Eistert 方法将这种酸的
乙酸酯转化为下一级同系物。与
碘甲烷进行格氏反应后得到 25-羟基
胆固醇(6),然后对其进行
溴化处理。最后用 LiAl3H4 处理 25-
溴胆固醇 (8),引入氚。