凉味剂3-L-薄荷氧基丙烷-1,2-二醇的合成研究

采用一种新方法,通过开环、水解两步反应合成了3-L-薄荷氧基丙烷-1,2-二醇凉味剂。首先用乙酸环氧丙醇酯与薄荷脑在路易斯酸催化作用下进行开环反应得到1-乙酰氧基-3-L-薄荷氧基丙烷-2-醇。开环的最佳条件为:三氟化硼乙醚为催化剂,反应温度0~10°C,反应时间4 h,薄荷脑与乙酸环氧丙醇酯摩尔比1.2∶1.0,催化剂与乙酸环氧丙醇酯摩尔比0.04∶1.0,收率70.5%。1-乙酰氧基-3-L-薄荷氧基丙烷-2-醇经NaOH水解得产物,在此反应中加入甲苯为溶剂,使反应易操作,收率为95.5%。并通过MS和1H NMR确定中间体和产物的结构。

Studies on Synthesis of 3-L-menthoxypropane-1,2 diol for Using as Cooling Agent

A new method was described for synthesis of 3-L-menthoxypropane-1,2-diol used as cooling agent by epoxide opening and hydrolysis.The epoxy ring of glycidyl acetate was opened by menthol in the presence of a Lewis acid to give 1-acetoxy-3-L-menthoxypropa-2-ol.The optimum conditions of epoxide opening were as follows: the catalyst,boron trifluoride ether complex;reaction temperature,0~10°C;reaction time,4 h;the molar ratio of menthol to glycidyl acetate,1.2∶1.0;and the molar ratio of boron trifluoride ether complex to glycidyl acetate,0.04∶1.The yield reached 70.5%.1-acetoxy-3-L-menthoxypropa-2-ol was hydrolyzed by NaOH in the presence of toluene to produce 3-L-menthoxypropane-1,2-diol.The reaction proceeded casily,and the yield reached 95.5%.The target compound was identified by MS and()~1H NMR.