Luo Yachun, Deng Xiaoyu, Zhang Yan, Sun Genlin, Yan Zhihong
Department of pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China.
Chirality. 2024 Jun;36(6):e23682. doi: 10.1002/chir.23682.
Obtaining optically pure compounds in an eco-friendly and cost-efficient manner plays an important role in human health and pharmaceutical industry. Racemic separation using multistage stereoselective liquid-liquid extraction has become one of the most practical and effective approach to access homochiral enantiomers. Currently, chiral ionic liquids (CILs) with structural designability have become a promising chiral additive and enable them as adjustable candidates for racemic separation. Herein, a high-effective stereoselective liquid-liquid extraction process composed of imidazolium cations and amino acid-derived anions as the chiral additive was established for racemic 2-cyclohexylmandelic acid (CHMA) separation. We have systematically investigated the choice of organic solvent, concentration of CIL, extraction temperature, and the pH of aqueous phase. For three-stage stereoselective extraction, the maximum enantiomeric excess (e.e.) for CHMA was reached up to 40.6%. Furthermore, the mechanism of steric effect and stereoselective capacity between the CILs and racemic CHMA was discussed and simulated. We envision that the work will facilitate the development of CILs in multistage liquid-liquid extraction and promote the large-scale production of optically pure enantiomers.
以环保且经济高效的方式获得光学纯化合物在人类健康和制药行业中发挥着重要作用。使用多级立体选择性液-液萃取进行外消旋体分离已成为获取纯手性对映体最实用且有效的方法之一。目前,具有结构可设计性的手性离子液体(CILs)已成为一种有前景的手性添加剂,并使其成为外消旋体分离的可调节候选物。在此,建立了一种由咪唑阳离子和氨基酸衍生阴离子作为手性添加剂组成的高效立体选择性液-液萃取工艺,用于外消旋2-环己基扁桃酸(CHMA)的分离。我们系统地研究了有机溶剂的选择、CIL的浓度、萃取温度和水相的pH值。对于三级立体选择性萃取,CHMA的最大对映体过量(e.e.)达到了40.6%。此外,还讨论并模拟了CILs与外消旋CHMA之间的空间效应和立体选择性能力的机制。我们设想这项工作将促进CILs在多级液-液萃取中的发展,并推动光学纯对映体的大规模生产。