不对称相转移催化合成L-苯丙氨酸的研究

【作者】 周凤儿；

【导师】 魏运洋；

【作者基本信息】 南京理工大学 ， 应用化学， 2004， 硕士

【摘要】 以甘氨酸乙酯盐酸盐和二苯甲酮为起始原料合成了N-二苯亚甲氨基乙酸乙酯，后者在手性相转移催化剂(+)-N-苄基氯化辛可宁诱导下与烷基化试剂溴化苄发生不对称相转移催化烷基化反应，水解得到L-苯丙氨酸。在此合成工艺的基础上，以苯甲醛代替二苯甲酮，同时改变相关的工艺条件对实验方案进行改进，取得了较好的实验结果。三步反应获得苯丙氨酸总化学收率由5.6％提高到43.3％，同时使L-苯丙氨酸的e.e．值提高到63％，显示改进工艺具有一定的理论价值和应用前景。此外，初步探讨了手性相转移催化剂(+)-N-苄基氯化辛可宁诱导不对称相转移催化烷基化反应机理，并讨论了碱的类型、反应溶剂、反应温度及反应时间等因素对反应对映选择性的影响。更多还原

【Abstract】 N-(diphenylmethylene) glycine ethyl ester was synthesized from glycine ethyl ester hydrochloride and benzophenone. L-Phenylalanine was then obtained by alkylation of N-(diphenylmethylene) glycine ethyl ester with benzyl bromide in the presence of an asymmetric phase-transfer catalyst (+)-N-benzyl-cinchonine chloride, followed by hydrolysis of the resulting product. On the basis of this process, better results were obtained by using benzaldehyde in place of benzophenone and improving process conditions. The overall yield of the product phenylalanine was increased from 5.6% to 43.3%, and the value of enantiomeric excess of L-phenylalanine was reached to 63%. The results showed that the improved process has certain theoretic and practical value. Furthermore, the asymmetric alkylation mechanism induced by the chiral phase-transfer catalyst (+)-N-benzyl-cinchonine chloride was discussed and the effects of reaction factors such as the kinds of base, reaction solvents, temperature and reaction time on the enantioselective of the reaction were studied.更多还原