由胆甾醇制备2-苯亚甲基-5α-胆甾烷-3-酮

Preparation of 2-Benzylidene-5α-cholestan-3-one from Cholesterol

以胆甾醇(■)为起始原料,通过10%Pd-C催化加氢还原合成5α-胆甾烷-3β-醇(■),■经Jones试剂氧化反应,得到5α-胆甾烷-3-酮(■),■经NaOH催化与苯甲醛发生Claisen-Schmidt缩合生成2-苯亚甲基-5α-胆甾烷-3-酮(■)。对制备工艺进行了优化,确定加氢反应的条件为:乙醇溶液中,25℃反应20 h;Jones试剂氧化反应的条件为:丙酮溶液中30℃反应2 h;Claisen-Schmidt缩合反应的条件为:乙醇溶液中,在NaOH催化下先25℃反应2 h,再升温至50℃反应3 h。优化条件下,3步反应总收率74.7%。产物结构经1H NMR、13C NMR和APCI-MS确证。

5α-Cholestane-3β-ol(■)was synthesized from cholesterol(■)by 10%Pd-C catalytic reduction,5α-cholestane-3-one(■)was synthesized by Jones reagent oxidation of■.And 2-benzylidene-5α-cholestan-3-one(■)was prepared by the Claisen-Schmidt condensation of■and benzaldehyde catalyzed by NaOH.The reaction process was optimized.The conditions of hydrogenation were 25℃in ethanol solution for 20 h,and those of Jones reagent oxidation were 30℃in acetone solution for 2 h.The reaction conditions of Claisen-Schmidt condensation were catalyzed by NaOH at 25℃for 2 h and subsequent 50℃for 3 h in ethanol solution.Under the optimized conditions,the total yield of the three-step reaction was 74.7%.The product structure was confirmed by1H NMR,13C NMR and APCI-MS.