Han Chao, Luo Jianguang, Xu Jinfang, Zhang Yingqi, Zhao Yucheng, Xu Xiaoming, Kong Lingyi
State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, Jiangsu, China.
State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, Jiangsu, China.
J Chromatogr A. 2015 Jan 2;1375:82-91. doi: 10.1016/j.chroma.2014.11.080. Epub 2014 Dec 4.
The use of a dinuclear Cu2(II)-β-cyclodextrin complex (Cu2-β-CyD) as a chiral selector (CS) was successfully applied to chiral high speed counter-current chromatography (HSCCC) for the enantioseparation of aromatic α-hydroxycarboxylic acids. α-cyclohexylmandelic acid (CHMA) as a case was studied to optimize the separation temperature, the pH value of the aqueous phase, and the concentration of the chiral selector, which were comparatively studied between Cu2-β-CyD and native β-cyclodextrin (β-CyD) as CSs. The thermodynamic parameters of the formation of the complex between the enantiomers and the CSs were obtained, and the complex formation constants between the enantiomers and Cu2-β-CyD or β-CyD were determined using induced circular dichroism technology. The results indicate that Cu2-β-CyD can remarkably improve the enantioseparation compared with β-CyD, mainly due to the ion-pairing interactions between the deprotonation of carboxyl group of CHMA and the Cu(II) ion of Cu2-β-CyD. Five of other aromatic α-hydroxycarboxylic acids were also enantioseparated successfully by HSCCC using Cu2-β-CyD as a CS.
双核Cu2(II)-β-环糊精配合物（Cu2-β-CyD）作为手性选择剂（CS）成功应用于手性高速逆流色谱（HSCCC），用于芳香族α-羟基羧酸的对映体分离。以α-环己基扁桃酸（CHMA）为例，研究了分离温度、水相pH值和手性选择剂浓度的优化，并对Cu2-β-CyD和天然β-环糊精（β-CyD）作为手性选择剂进行了比较研究。获得了对映体与手性选择剂之间形成配合物的热力学参数，并采用诱导圆二色技术测定了对映体与Cu2-β-CyD或β-CyD之间的配合物形成常数。结果表明，与β-CyD相比，Cu2-β-CyD能显著提高对映体分离效果，主要是由于CHMA羧基去质子化与Cu2-β-CyD的Cu(II)离子之间的离子对相互作用。另外五种芳香族α-羟基羧酸也以Cu2-β-CyD作为手性选择剂通过HSCCC成功实现了对映体分离。
