Wittig反应及其在维生素A和类胡萝卜素合成中的应用-化学专业毕业论文.docx

摘要
本文概述了Wittig反应及其在维生素A、虾青素和加丽素红的合成中的应用。同时介绍了Wittig反应的几个重要部分:叶立德,碱和反应介质;Wittig反应中稳定叶立德、活泼叶立德及半稳定叶立德的立体化学。Wittig反应的主要特点是在于所生成的碳碳双键的位置是完全确定的,并且这类反应是在碱性介质中, 在室温或稍高于室温(某些情况下在低温)进行的。因此比较适合于合成维生素类及类胡萝卜素等烯烃化合物。
本文研究了采用Wittig路线合成维生素A酯的方法,此法反应步骤少,产品纯度较好,成本较低,为国内的维生素A酯的工艺路线改进提供了可靠的数据;合成出虾青素和斑蝥黄,并且进行了中试,为即将的工业化奠定了坚实的基础,填补了国内的空白;用一锅法合成并异构维生素A酯,得到90%以上全反式的混合品,使下一步结晶更为便利,大于文献报道;首次提出了Wittig
法合成维生素A酯的动力学模型;首次采用量化计算的半经验方法对本实验的异构进行了计算,和实验结果吻合良好,很好的指导了实验。
关键词:Wittig,维生素A,虾青素,斑螫黄,量化,异构
枣獬、导嗣簟
匆垒文公韶
浙江大学理学硕士学位论文
Abstract
This dissertation review the application of Wittig reaction anic synthesis and synthesis of vitamin A, astaxanthin and described some important parts of Wittig reaction ylide,alkali and medium;stereochemistry of stabilized ylide, semi—stabilized ylide and non—stabilized ylide, main character of Wittig reaction is that the position of C··C double--bond is
completely the reaction take place was in condition of base,room temperature or little higher(10w temperature at some condition).So this reaction is fitted for the synthesis of pound, such as vitamins,carotenoids.
This dissertation study the synthesis of Vitamin A acetate used in Wittig Reaction,with few steps of reaction,higher pure production and low we provide the reliable date for the improved process of vitamin A acetate in China;Continuous process to synthesis and isomerization of vitamin A acetate Can get 90%or high all—trans product, which is higher than literature;We have established the dynamical model of synthesis of vitamin A actetate for the first isomerization
reactions have been studied using quantum chemistry methos at
semi—empirical result agree well with experiment
浙江大学理学硕士学位论文
Keyword:Wittig,vitamin A,astaxanthin,canthaxanthin,quantum
chemistry,isomerization
.-3..
浙江大学理学硕士学位论文
第一章前言
Wittig反应的优点在于所生成的碳碳双键的位罱是完全确定的,即双键出现在原来羰基的位置,而不像经由Grignard试剂反应(所得的醇再脱水)合成烯烃时所发生的双键移位或碳骨架重排生成烯烃异构体。同时这类反应是在碱性介质中, 在室温或稍高于室温(某些