Department of Pharmacy, King's College London, SE1 9NH, London, UK.
J Chromatogr A. 2010 Feb 12;1217(7):1149-56. doi: 10.1016/j.chroma.2009.09.035. Epub 2009 Sep 17.
It is believed that the enantiorecognition mechanism based on macrocyclic antibiotics involves multimodal interactions via hydrogen bonding, pi-pi interaction, steric hindrance, hydrophobic interaction and so on. A variety of enantiomeric N-benzoylated amino acids were separated using balhimycin (A) or its analogues bromobalhimycin (B) and dechlorobalhimycin (C) as chiral mobile phase additive using a CE method, which combined the partial filling technique with the dynamic coating technique and the co-EOF electrophoresis technique. The enantioresolution and the migration time were highly relevant to the structure of analytes, especially to the substitutions on the N-tagged benzoyl moiety of the amino acids. A steric effect and pi-pi interaction based mechanism is proposed in order to explain some observed enantioresolution differences between positional isomers. Notably dechlorobalhimycin exhibited the best enantioresolution for several N-benzoylated derivatives of leucine, which was rarely observed for N-dansylated amino acid derivatives. The hydrophobicity difference of the aglycone pocket among three chiral selectors was assumed to account for this behaviour.
据信，基于大环抗生素的对映体识别机制涉及通过氢键、π-π 相互作用、空间位阻、疏水相互作用等多种模式相互作用。使用巴拉霉素 (A) 或其类似物溴巴拉霉素 (B) 和去氯巴拉霉素 (C) 作为手性流动相添加剂，通过 CE 方法分离了各种对映体 N-苯甲酰化氨基酸，该方法结合了部分填充技术、动态涂层技术和共电渗流电泳技术。对映体分离度和迁移时间与分析物的结构高度相关，特别是与氨基酸的 N-标记苯甲酰部分的取代基有关。提出了一种基于空间效应和 π-π 相互作用的机制，以解释观察到的位置异构体之间的一些对映体分辨率差异。值得注意的是，去氯巴拉霉素对几种 N-苯甲酰化亮氨酸衍生物表现出最佳的对映体分辨率，而这在 N-丹酰化氨基酸衍生物中很少观察到。假设三种手性选择器中糖苷口袋的疏水性差异可以解释这种行为。
