含氨基酸单元手性脲的对映体识别性能研究

doi:10.11938/cjmr20243141

摘要/Abstract

摘要：

手性分子识别对于化学及制药行业至关重要，我们合成了三种含氨基酸结构单元的手性脲（L-Phe-U、L-Ala-U以及L-Val-U）作为手性溶剂化试剂，利用NMR技术对含有不同取代基的手性有机羧酸分子进行对映体识别. 在4-二甲氨基吡啶的辅助作用下，L-Phe-U对不同的有机羧酸都具有一定的手性识别能力，R型和S型C_αH基团¹H的化学位移差（ΔΔδ）范围可达2.4 ~ 16 Hz，同时能够准确测定RS-扁桃酸的对映体过量值. 通过比较发现手性溶剂化试剂含有的苯基及底物手性碳中心连接的基团都会影响手性脲的识别能力. 我们利用DOSY实验测定了扁桃酸在不同体系下的扩散系数，对R型和S型对映体进行区分，揭示了其手性识别的动力学变化.

关键词: 核磁共振（NMR）, 手性溶剂化试剂, 手性羧酸, 对映体识别, 化学位移差, 对映体过量

Abstract:

Recognition of chiral molecules is critical for the chemical and pharmaceutical industries. Three kinds of urea containing chiral centers (L-Phe-U, L-Ala-U and L-Val-U) were synthesized as chiral solvating agents (CSAs) to identify chiral organic carboxylic acids with different substituents, whose chiral anion recognition properties were further examined by NMR spectroscopy. In the presence of 4-dimethylaminopyridine (DMAP), enantiomeric signals of the benzylic C-H protons of mandelic acid were observed when mixed with L-Phe-U. The ΔΔδ values of the C_αH signals ranged from 2.4 to 16.0 Hz, and the enantiomer excess (ee) value of RS-rac-mandelic acid (rac-MA) can be determined accurately. It was found that the phenyl group contained in chiral solvating agents and the groups connected to the chiral carbon center of substrates would affect the separation of enantiomeric signals. Moreover, DOSY spectra reveal that the diffusion coefficients of rac-MA enantiomers differ in the chiral solvating agents, providing insights into the dynamics of chiral recognition.

Key words: nuclear magnetic resonance (NMR), chiral solvating agents, chiral carboxylic acid, enantiomeric recognition, chemical shift difference, enantiomeric excess

中图分类号:

O482.53

寇新慧, 张玉冰. 含氨基酸单元手性脲的对映体识别性能研究[J]. 波谱学杂志, 2025, 42(3): 221-230.

KOU Xinhui, ZHANG Yubing. Study on the Enantiomeric Recognition of Chiral Ureas Containing Amino Acid Units[J]. Chinese Journal of Magnetic Resonance, 2025, 42(3): 221-230.

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序号	手性化学位移试剂	ΔΔδ/Hz
1	L-Phe-U	15.2
2	L-Phe-U	9.6
3	L-Phe-U	2.4
4	L-Phe-U	11.2
5	L-Phe-U	0.64
6	L-Phe-U	2.4
7	L-ALa-U	3.2
8	L-ALa-U	4.0
9	L-ALa-U	3.6