D-色氨酸的合成工艺研究

Improved Synthesis of D-Tryptophan

在甲醇钠碱性条件下,以芦竹碱和N-乙酰氨基丙二酸二乙酯为原料进行缩合反应,缩合产物在4%的氢氧化钠水溶液中选择性水解脱羧得到N-乙酰-DL-色氨酸,然后在10%氢氧化钠水溶液中水解得到DL-色氨酸。DL-色氨酸用D-酒石酸拆分,并在苯甲醛催化下实现不对称转化,得到D-色氨酸D-酒石酸盐,最后用三乙胺中和得到目标产物D-色氨酸。确定了缩合和拆分步骤的适宜工艺条件。缩合步骤:甲醇钠摩尔量为芦竹碱的20%,n(芦竹碱)∶(N-乙酰氨基丙二酸二乙酯)=1∶1.2;拆分步骤:乙酸为溶剂,70℃反应,苯甲醛摩尔量为DL-色氨酸的10%,n(DL-色氨酸)∶n(D-酒石酸)=1∶2。

Gramine reacted with diethyl acetamldomalonate in the presence of sodium methoxide, the intermediate was selectively hydrolyzed in 4% aqueous solution of sodium hydroxide to give N-acetyl-DL- tryptophane, then DL-tryptophane was obtained through hydrolyzation using 10% aqueous solution of sodium hydroxide. The resolution was carried out with D-tartaric acid to give D- tryptophane D- tartaric acid salt, and benzaldehyde was used as catalyst to make asymmetric transformation. At last the salt was neutralized with triethylamine to give D-tryptophane. The optimum reaction conditions for condensation and resolving reaction were studied. For condensation reaction the molar ratio of sodium methoxide and gramine was 20%, and gramine ： diethyl acetamidomalonate= 1 ： 1.2 （tool） ; For resolving reaction acetic acid was used as solvent, 70℃ ,the molar ratio of benzaldehyde and DL-tryptophan was 10%, and DL- tryptophane ： D-tartaric acid= 1 ： 2（mol）.