Chiralpak AD-H和Chiralcel OJ-H手性固定相拆分扁桃酸系列化合物

对比了商品化的淀粉型手性固定相Chiralcel OJ-H和纤维素型手性固定相Chiralpak AD-H柱在正相条件下对扁桃酸系列8个化合物的拆分，结果表明Chiralcel OJ-H柱对扁桃酸系列化合物具有更强的手性识别能力，8个外消旋扁桃酸化合物在36 min内都得到了基线分离。研究发现，扁桃酸苯环上的取代基对其拆分的难易程度影响很大，其电子诱导效应影响扁桃酸类化合物在固定相上的保留时间，其空间位阻效应是扁桃酸在固定相上被拆分成败的决定因素。通过对比分析扁桃酸和手性柱的结构，探讨了可能的手性拆分机理是基于Chiralpak AD-H(Chiralcel OJ-H)手性固定相和扁桃酸系列化合物之间的氢键-氢键、偶极-偶极、π-π电子相互作用以及空间适应性等诸多因素的综合影响，其中空间适应性起到至关重要的作用。本研究可为一些实际光学活性扁桃酸及其类似物的对映体纯度测定与拆分研究提供参考。

Enantioseparation of mandelic acid compounds with Chiralpak AD-H and Chiralcel OJ-H chiral stationary phases

Eight mandelic acid compounds were enantioseparated with amylose-based chiral stationary phase Chiralcel OJ-H and cellulose-based chiral stationary phase Chiralpak AD-H, in the normal-phase mode. It showed that Chiralcel OJ-H exhibited higher enantioseparation, and the eight mandelic acid compounds can be baseline separated in 36 min by Chiralcel OJ-H. Also, the substituents in the aromatic ring of mandelic acid compounds have great influence on the degree of difficulty in the resolution of mandelic acids. The negative inductive effect will reduce the retention time of the mandelic acid compounds on the stationary phase while the positive inductive effect will increase the retention time of the mandelic acid compounds. The steric hindrance effect of the substituents is the key factor influencing the success or failure of the resolution. The possible mechanism of chiral recognition is discussed by comparison and analysis of the differences in their structures. Many factors contribute to enantioseparation of the mandelic acids, including the hydrogen bonds, dipole-dipole interactions, π-π interactions and spatial adaptability between chiral stationary phases and the mandelic acids. Among them, the spatial adaptability plays a crucial role in the resolution of the mandelic acids. This study provides a reference for the enantiomeric purity determination and resolution of some practical optically active mandelic acid and its analogs.