7-脱氢胆固醇的合成工艺研究

Study on the Synthesis of 7-Dehydrocholesterol

胆固醇在石油醚中与醋酸酐反应得到胆固醇醋酸酯,经2,4,4,6-四溴-2,5-环己二烯酮处理得到7-溴化胆固醇酯,再用2,4,6-三甲基吡啶脱溴得到7-脱氢胆固醇醋酸酯,最后水解得到目标产物7-脱氢胆固醇.对上述四步反应条件进行了研究,第三步以2,4,4,6-四溴-2,5-环己二烯酮为溴化剂,具有选择性高、反应条件温和、产率高等特点.四步总收率(以胆固醇计)达68.9%.

7 - Dehydrocholesteml has been synthesized from cholesterol through acylation, bmmination, dehydrobromination and hydrolyzation. The conditions of the above four-step reaction have been studied. Adopting 2,4,4,6 - tertrabmmo - 2,5 - cyclohexadie - none as the chlorinating agent, the chlorination is found to be high in selectivity, mild in reaction condition and good in yield.The total yield of the four-step reaction is 68.9% （based on cholesterol）.