对甲氧基肉桂酸正丁酯的合成

实验以两步法合成了甲氧基肉桂酸正丁酯。第一步,以甲醇钠为催化剂,由对甲氧基苯甲醛和乙酸甲酯经Claisen-Schmidt缩合反应先合成对甲氧基肉桂酸甲酯,在对甲氧基苯甲醛用量50 mmol、n(对甲氧基苯甲醛):n(乙酸甲酯)=1:8、甲醇钠用量为反应混合物的10%、反应温度50℃、反应时间1.0 h的较佳实验条件下,产物对甲氧基肉桂酸甲酯收率达79.0%。第二步,以硫酸氢钠为催化剂,由对甲氧基肉桂酸甲酯与正丁醇经酯交换反应合成对甲氧基肉桂酸正丁酯,较佳工艺条件为:对甲氧基肉桂酸甲酯4.8 g,n(对甲氧基肉桂酸甲酯):n(正丁醇)=1:7,硫酸氢钠用量为对甲氧基肉桂酸甲酯的10%,反应时间4 h。该条件下,对甲氧基肉桂酸甲酯转化率达88.0%,对甲氧基肉桂酸正丁酯的选择性近100%。

SYNTHESIS OF(E)-BUTYL-3-(4-METHOXYPHENYL) ACRYLATE

The synthesis of (E)-butyl-3-(4-methoxyphenyl) acrylate was studied with a two-step method.Firstly,using sodium methoxide as a catalyst,methyl p-methoxy cinnamate was prepared by the Claisen-Schmidt condensation of p-methoxybenzaldehyde and methyl acetate,and the optimum conditions were obtained as follows: 50 mmol p-methoxybenzaldehyde,n(p-methoxybenzaldehyde): n(methyl acetate) = 1:8,10% sodium methoxide based on the mixture,reaction temperature 50 ℃ and reaction time 1.0 h.Under the above conditions,the yield of methyl p-methoxy cinnamate was 79.0%.Secondly,(E)-butyl-3-(4-methoxyphenyl) acrylate was synthesized by the transesterification of methyl p-methoxy cinnamate with n-butanol over sodium bisulfate,and the influences of the reaction conditions were examined.The results showed that,under the optimum conditions:4.8 g methyl p-methoxy cinnamate,n(methyl p-methoxy cinnamate):n(n-butanol) = 1:7,10% sodium bisulfate based on methyl p-methoxy cinnamate,refluxing 4 h,the conversion of methyl p-methoxy cinnamate was 88.0% and the selectivity of the product was nearly 100%.The structures of the two products were confirmed by FT-IR and ~1H NMR.