3-甲酰基丁-2-烯基乙酸酯的合成

Synthesis of 3-Formylbut-2-Enyl Acetate

维生素A工艺路线C15+C5的重要中间体C5,即3-甲酰基丁-2-烯基乙酸酯。其合成方法很多,但都存在各种各样的缺点,二甲氧基丙酮法步骤多,收率低;环氧乙烷法原料危险,技术难度大;异戊二烯法原料贵重,废水量大;丁烯二醇法条件严格、设备投入大。采用氯乙醇为起始原料,经乙酸酐酯化,亚膦酸酯保护,与1,1-二甲氧基丙酮反应,得到3-缩醛-2-烯基乙酸酯,脱保护基得3-甲酰基丁-2-烯基乙酸酯,总摩尔收率64.7%。本方法具有反应条件温和,原料易得,三废少,产品纯度高,设备投入小的优点。

Vitamin A intermediated C5, namely 3-formylbut-2-enyl acetate, which was used C15＋C5 synthesis route of vitamin A. Vitamin A can be synthesized by various methods. However there were defects in these approaches. 1,1-dimethoxy-2-propanone method had complicated synthesis procedures and low product yield, there were hazard materials and great technical difficulties in the oxirane method, high-cost materials need to be used in the isoprene method and this route may generate substantial wastewater capacity, and the 2-butene-1,4 -diol method need strict conditions and costly devices. 2-Chloro-1-ethanol was used as starting material, esterified by acetic anhydride and protected by phosphate ester, and then reacted with 1,1 -dimethoxy -2propanone, trans - γ - acetoxytiglic aldehyde dimethyl acetal can be obtained, subsequently deprotection and 3-formylbut-2-enyl acetate can be achieved. By this method, the process had advantages of mild reaction conditions, cheap raw materials, few wastes, high purity and low equipments cost.