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以3,4,5-三甲氧基苯甲醛为原料,经二氯卡宾反应、还原反应两步合成了米库氯铵的重要中间体——3,4,5-三甲氧基苯乙酸。较佳的合成工艺条件为:(1)二氯卡宾反应:以0.3 mol 3,4,5-三甲氧基苯甲醛为基准,在n(3,4,5-三甲氧基苯甲醛)∶n(CHCl3)=1∶3,复合相转移催化剂(PTC)2 g,w(NaOH)=40%的水溶液21 mL,反应温度60℃,反应时间7 h的条件下,反应收率为71.7%;(2)还原反应:以0.1 mol 3,4,5-三甲氧基扁桃酸为基准,在n(3,4,5-三甲氧基扁桃酸)∶n〔(CH3)3SiCl〕∶n(NaI)∶n(Zn)=1∶1.25∶1.25∶3,反应温度80℃,“一锅法”反应5 h的条件下,反应收率91.0%。两步反应总收率为65.2%。产物结构通过IR、1HNMR进行表征。
Using 3,4,5-trimethoxybenzaldehyde as raw material, 3,4,5-trimethoxyphenylacetic acid, an important intermediate of MikuClock, was synthesized by two steps reaction of dichlorocarbene and reduction. The preferred synthesis conditions are: (1) Dichlorocarbene reaction: based on 0.3 mol of 3,4,5-trimethoxybenzaldehyde, n (3,4,5-trimethoxybenzaldehyde): n (CHCl3) = 1: 3, 2 g of composite phase transfer catalyst (PTC) and 21 mL of aqueous solution of w (NaOH) = 40% at a reaction temperature of 60 ℃ and a reaction time of 7 h. (2) Reduction reaction: Based on 0.1 mol of 3,4,5-trimethoxymandelic acid, n (3,4,5-trimethoxymandelic acid): n [(CH3) 3SiCl]: n ): N (Zn) = 1: 1.25: 1.25: 3, reaction temperature 80 ℃, reaction time 5 h. The total yield of the two-step reaction was 65.2%. The product structure was characterized by IR, 1HNMR.