2,4,5-涕丙酸的NMR手性分离条件

An Effective NMR Chiral Solvating Agent for2-(2,4,5- Trichlorophenoxy)propanoic Acid

以1,2_二苯基二氨基乙烷 (简称DPEDA ,化合物1)的(1R,2R)体 (简称(R)_1)为手性溶剂 (CSA) ,解决了外消旋2,4,5_涕丙酸(化合物2)在氯仿溶剂中溶解性不良的问题 ,并且化合物2的1H谱获得了出色的手性分离效果 ;通过研究包括温度、浓度、底物与CSA的摩尔比、CSA结构等影响化学位移不等价的因素得出结论 ,对于手性中心CH ,在化合物2与(R)_1的摩尔比为2∶1时 ,提高底物浓度和降低测试温度有利于增加手性分离度 ;而对于与手性中心相连的CH3,增大(R)_1的比例,减小底物浓度,提高测试温度 ,有利于增大ΔδH;化合物1的(1S,2S)体 (简称(S)_1)与(R)_1具有相同的手性分离作用 ;另外还对各影响因素的作用机理进行了探讨。

R,2R)- or(1S,2S)-1,2-diphenylethane-1,2-diamine(DPEDA,compound1)not only imˉproves the solubility of2-(2,4,5-trichlorophenoxy)propanoic acid(compound2)in chloroform,but also acts as an effective chiral solvating agent(CSA)in the 1 H NMR analysis of the enantiomeric purity of compound2.The effect of temperature,stoichiometric ratio,concentration and solvating agent structure on the observed shift non- equivalence were studied.The optimal conditions were found.The shift non-equivalence for the chiral center CH will be improved by using a high concentration and a lowtemperature with the stoichiometric ratio of compound2to(1R,2R)-DPEDA((R)-1)of2∶1,but the shift non-equivalence of CH 3 linking the CH will be improved by using a low concentration and a high temperature with the high ratio of(R)-1.(1S,2S)-DPEDA has the same effect as(R)-1,moreover,the mechanism of effect for different affecting factors were discussed.