L-酒石酸正丁酯萃取拆分酮洛芬外消旋体

研究了酮洛芬对映体在含疏水性手性选择体L-酒石酸正丁酯的1,2-二氯乙烷和甲醇水两相体系中的萃取分配行为.考察了酒石酸酯的种类、L-酒石酸正丁酯的浓度、有机溶剂的种类及甲醇溶液的浓度对分配系数K和分离因子α的影响.L-酒石酸正丁酯与S-酮洛芬对映体比L-酒石酸正丁酯与R-酮洛芬对映体形成更稳定的非对映体复合物;以0.2mol/L L-酒石酸正丁酯为手性选择体,以1,2-二氯乙烷为有机溶剂,甲醇浓度为10％时,萃取分离效果最好.     

羟丙哌嗪手性拆分的HPCE新方法

以组氨酸-β-环糊精（β-CD-E_2）衍生物作为手性选择剂，利用原位聚合反应制得新型β-CD衍生物手性高效毛细管电泳（HPCE）整体柱，将其应用于手性药物羟丙哌嗪的消旋体拆分。分别探究了不同缓冲体系的洗脱能力、缓冲液pH对分离的影响以及羟丙哌嗪手性拆分的线性范围。结果表明，在最佳条件下，羟丙哌嗪对映体在β-CD-E_2整体柱上能得到较好拆分，分离度Rs达到40.52，且羟丙哌嗪浓度在9.8×10~(-6)～2.0×10~(-5)mol/L范围内与对映体峰高、峰面积具有一定的线性关系。此工作将β-CD-E_2作为HPCE固定相，为手性药物羟丙哌嗪建立了一种新的分离分析体系。     

双相识别手性液液萃取系统拆分氟比洛芬对映体

氟比洛芬是临床上常用的非甾体抗炎类手性药物,主要用于治疗类风湿性关节炎和骨关节炎。其S型对映体有较高的药理活性而R型对映体药效较低且有一定毒副作用,因此获得单一的光学纯S-氟比洛芬对映体具有重要应用价值。在之前工作基础上,研究利用含手性离子液体为水相萃取剂和酒石酸酯为油相萃取剂的双相识别手性萃取系统对氟比洛芬消旋体进行了手性拆分。研究了酒石酸酯种类,有机溶剂种类,油相手性选择剂浓度,氟比洛芬消旋体浓度,pH及温度对萃取过程的影响,并通过反萃取过程实现了手性离子液体的循环回用。结果表明,在1-丁基-3-甲基咪唑L-色氨酸([Bmim][L-trp])浓度0.02 mol·L~(-1),D-酒石酸二辛酯浓度0.3 mol·L~(-1),氟比洛芬浓度50μg·mL~(-1),二氯乙烷为有机溶剂,pH=2.0,25℃下,体系选择性达到1.31。相比于单相手性识别,双相手性识别体系选择性得到较大改善。     

离子液体/盐双水相双相识别体系在α-环己基扁桃酸对映体拆分中的应用研究

研究了α-环己基扁桃酸(α-CHMA)对映体在以含羟丙基-β-环糊精(HP-β-CD)和D-(-)-酒石酸二异丙酯为手性识别剂的离子液体/盐双水相体系中的萃取分离行为。固定离子液体1-丁基-3-甲基咪唑四氟硼酸盐([C4mim]BF4)及硫酸铵的含量,考察体系D-(-)-酒石酸二异丙酯添加量、HP-β-CD浓度及p H等因素对α-CHMA对映体分配系数(D)及分离因子(α)的影响。实验结果表明:在所考察体系中,双相识别比单相识别的分离效果更优;优化分离条件,分离因子可达1.68。     

毛细管电泳法分离6种手性化合物

以羟丙基-β-环糊精作为手性选择剂,采用毛细管电泳法对氧氟沙星、特布他林、克伦特罗、美托洛尔、扁桃酸和苯基丁二酸等6种对映体进行手性分离条件研究。通过对羟丙基-β-环糊精的浓度、缓冲溶液pH值、电压和检测波长等影响手性分离主要因素的探讨,建立了能同时实现对6种对映体手性分离的方法;并采用对照品加入法将手性单体加入到对映体化合物中,确定了氧氟沙星对映体的出峰顺序。     

羟丙基-β-环糊精萃取苯基琥珀酸的动力学特性

为研究β-环糊精衍生物类萃取剂萃取芳香酸对映体的动力学行为,以苯基琥珀酸对映体（PSA）为分离溶质,羟丙基-β-环糊精（HP-β-CD）为萃取剂,采用恒界面池法考察了搅拌速率、两相接触面积、萃取剂和溶质浓度等操作参数对苯基琥珀酸对映体萃取动力学的影响。实验结果表明：HP-β-CD萃取PSA为准一级反应萃取过程;且萃取发生在相界面,萃取速率随PSA的初始浓度的增大而增大,且呈线性关系。     

手性萃取剂与液-液萃取拆分对映体技术研究进展

手性对映体的拆分是当前备受关注的一个研究领域。手性对映体的拆分方法有多种, 手性液-液萃取拆分法是其中有较好发展前景的一种手性对映体拆分技术。本文概述了手性液-液萃取技术的基本原理, 并进一步对酒石酸类手性萃取剂、环糊精类手性萃取剂、冠醚类手性萃取剂、金属络合物类手性萃取剂等不同种类手性萃取剂及其研究进展进行了综述。分析表明, 手性液-液萃取拆分技术对外消旋体特别是药物外消旋体的拆分有较好的效果, 随着对手性萃取剂研究的进一步深入, 手性液-液萃取有望成为一种手性化合物拆分的重要方式。     

HPLC手性流动相添加剂法拆分盐酸美西律对映体

以羟丙基-β-环糊精(HP-β-CD)作为手性流动相添加剂,于C18柱高效液相色谱建立了盐酸美西律对映体的拆分方法.方法:本文选用ODS Hypersil柱(4.6 mm×200 mm,4.5μm),以羟丙基-β-环糊精(HP-β-CD)作为手性流动相添加剂,流动相:乙腈-水(30:70,v/v),其中含17mmol·L-1HP-β-CD.pH值为6.32,流速0.20mL·min-1;紫外检测波长:261nm;进样量:10μL.考察了流动相种类、pH值和手性流动相添加剂浓度等因素对手性拆分的影响.结果:建立了羟丙基-β-环糊精手性流动相添加剂法拆分盐酸美西律对映体的方法.结论:此方法简便、快速,分离度好.     

疏水性L-酒石酸酯萃取分离氧氟沙星对映体

研究了氧氟沙星对映体在含有不同烷基链的L-酒石酸酯手性选择体的水-有机溶剂两相系统中的萃取分配行为,考察pH值对氧氟沙星对映体在两相中分配系数（K）和分离因子（α）的影响,同时研究了正庚烷、1,2-二氯乙烷和醇等溶剂化效应和萃取平衡时间.实验表明,L-酒石酸酯与R-氧氟沙星对映体形成非对映体复合物的稳定性比与S-氧氟沙星对映体形成的非对映体复合物大;所用L-酒石酸酯手性选择体随着取代烷基链的增长,分配系数和分离因子增大; 有机溶剂的性质对R-和S-氧氟沙星两对映体分配系数和分离因子影响很大;适合萃取分离氧氟沙星对映体的pH值约等于7.     

氨基酸离子液体液液萃取拆分美托洛尔的研究

美托洛尔是一种常用的β_1受体阻断剂,在临床上被广泛用于心血管疾病的治疗。研究表明S-对映体具有较强的药效,而R-对映体与一些毒副作用相关。因此获得单一构型的S-美托洛尔对提高药物的安全性和有效性有重要意义。采用氨基酸离子液体作为手性识别剂用于手性液液萃取拆分美托洛尔对映体。研究氨基酸离子液体种类和浓度,有机溶剂,美托洛尔初始浓度,水相pH以及温度对萃取分配行为的影响。结果表明,当采用1,2-二氯乙烷作为有机溶剂,1-丁基-3-甲基咪唑L-色氨酸([Bmim][L-Trp])作为手性识别剂,手性识别剂和美托洛尔浓度分别为30和2mmol×L~(-1),水相pH为8.5,温度为25℃时,对映体选择性达到1.29。研究成果为手性液液萃取拆分法的工业化应用提供参考。     

Enantioselective separation of R,S-phenylsuccinic acid by biphasic recognition chiral extraction

A new process has been developed to separate phenylsuccinic acid (H₂A) enantiomers, based on the oppositely preferential recognition of hydrophobic and hydrophilic chiral selectors in organic and aqueous phases, respectively, which is named as biphasic recognition chiral extraction (BRCE). BRCE system is established by adding hydrophobic l-iso-butyl tartrate in organic phase and hydrophilic β-cyclodextrin (β-CD) derivative in aqueous phase, which preferentially recognize S-H₂A and R-H₂A, respectively. The studies performed involve two enantioselective extractions in a biphasic system, where H₂A enantiomers form four complexes with β-CD derivative in aqueous phase and l-iso-butyl tartrate in organic phase, respectively. Here it is shown that the efficiency of the extraction depends, often strongly, on a number of process variables, including the types of organic solvents and β-CD derivatives, iso-butyl tartrate configurations, the concentrations of the extractants and H₂A enantiomers, pH and temperature. Phase-equilibria in BRCE systems is governed by the complex chemical equilibria in both the organic and aqueous phases. By changing the monophasic recognition chiral extraction (MRCE) system into BRCE system, the enantioselectivity increases from 1.501 to 2.862. The maximum enantioselectivity for H₂A enantiomers is obtained at pH≤2.5 and the ratio of 2:1 of [l-(+)-iso-butyl tartrate] to [HP-β-CD]. The experimental results show that BRCE is of much stronger chiral separation ability than MRCE, which is due to utilization of the separation abilities of both tartrate and β-CD derivative. It may be very helpful to optimize the extraction systems and realize the large-scale production of pure enantiomers.     

Selective Enantioseparation of Racemic Amlodipine by Biphasic Recognition Chiral Separation System

The biphasic recognition chiral extraction process was developed and applied to separate amlodipine enantiomer. The chiral extraction system contained tartaric acid derivatives in the organic phase and β-cyclodextrin derivatives in the aqueous phase. The effect of extraction equilibrium time and the influence of different types of tartaric acids, types of β-cyclodextrin derivatives, organic solvents, and buffer pH were investigated. The results indicated that hydroxypropyl-β-cyclodextrin (HP-β-CD) showed a higher recognition ability toward (S)-amlodipine than (R)-amlodipine while dibenzoyl-D-tartrate demonstrated the strongest ability among tartaric acid derivatives to bind with (R)-amlodipine. The distribution ratios for (S)-amlodipine (k_S) and (R)-amlodipine (k_R) gave optimum values at pH 5.0 of 16.54 and 0.78, respectively. Biphasic chiral recognition extraction has great significance for preparative separation of (S)-amlodipine. It can also be used to design and apply the enantioseparation process.     

Determination of Kinetics in Biphasic Recognition Chiral Extraction for Separation of Phenylsuccinic Acid Enantiomers

This paper reports on the determination of the intrinsic kinetics in biphasic recognition chiral extraction of phenylsuccinic acid enantiomers (H₂A) by L-IBTA and HP-β-CD in a modified Lewis cell. The two-phase homogeneous reaction model was selected, because there is a finite physical solubility of phenylsuccinic acid enantiomers in both the aqueous phase and the organic phase. The regime analysis was split up in three parts: a regime analysis on the aqueous phase reaction in the absence of organic phase reaction, a regime analysis of the organic phase reaction in the absence of the aqueous phase reaction, and a regime analysis of reactions in both phases. The reactions have been found to be first order with respect to H₂A and second order with respect to L-IBTA and HP-β-CD. Competitive extraction of H₂A enantiomers with HP-β-CD and L-IBTA has great influence on the extraction process. With increase of HP-β-CD concentration, high enantioselectivity was obtained, but the extraction rate decreases.     

Reaction kinetics in reactive extraction for chiral separation of α-cyclohexyl-mandelic acid enantiomers with hydroxypropyl-β-cyclodextrin

This paper reports on determination of the intrinsic reaction kinetics in reactive extraction of α-cyclohexyl-mandelic acid (α-CHMA) enantiomers with hydroxypropyl-β-cyclodextrin (HP-β-CD) in a modified Lewis cell, in which HP-β-CD dissolved in 0.1 mol/l NaH₂PO₄/H₃PO₄ buffer solution was selected as chiral extractant. α-CHMA enantiomers were extracted from an organic phase to an aqueous phase in the extraction module. The theory of extraction accompanied by chemical reactions has been used to obtain the intrinsic kinetics of this extraction module. The different factors affecting the extraction rate, such as agitation speed, interfacial area, initial enantiomers concentration in an organic phase as well as HP-β-CD concentration in an aqueous phase were separately studied. The experimental results demonstrate that the extraction reaction kinetics is fast. The reactions between α-CHMA enantiomers and HP-β-CD in a stirred cell fall in regime 3 and are first order with respect to α-CHMA enantiomers and second order with respect to HP-β-CD with forward rate constants of 6.9×10⁻² m⁶/(mol² s) and 2.5×10⁻² m⁶/(mol² s) for S-α-CHMA and R-α-CHMA, respectively. These data will be useful in the design of the extraction process.     

Enantioselective Separation of Racemic Amlodipine by Two-Phase Chiral Extraction Containing O,O′-Dibenzoyl-(2S,3S)-Tartaric Acid as Chiral Selector

A two-phase chiral extraction system containing O,O′-dibenzoyl-(2S,3S)-tartaric acid ((+)-DBTA) in 1-decanol organic phase and aqueous phase was developed for the chiral resolution of amlopidine. The effects of extractant concentration, equilibrium time, and pH of the aqueous phase on the separation performance were investigated. The results indicated that the system afforded a strong chiral separation ability; the (+)-DBTA showed a higher recognition ability toward (S)-amlodipine than the (R)-amlodipine. Upon a single extraction, the enantiomeric excess (%) of (S)-amlodipine could be enriched to 24.27%. The product recovery ratio was 0.74. The distribution ratios for (S)-amlodipine (D _S ), (R)-amlodipine (D _R ) and separation factor (α) were 1.28, 0.78, and 1.64, respectively. Therefore, the pH and concentration of the extractant have the great effects on chiral separation ability. Two-phase chiral extraction has great significance for preparative separation of (S)-amlodipine; it can also be used to design and scale up the enantioselective separation process.     

手性流动相添加剂法拆分盐酸依替福林对映体

建立了以羧甲基-β-环糊精(CM-β-CD)作为手性流动相添加剂,高效液相色谱拆分标题化合物的方法。系统考察了流动相中添加剂的种类及浓度、有机修饰剂、pH、三乙胺的含量和流速等因素对拆分的影响。色谱分离条件:流动相(V(甲醇)∶V(乙腈)∶V(水)=15∶70∶15),CM-β-CD浓度为0.6 g/L,三乙胺含量为0.14%(V/V),pH为3.92,流速为0.2mL/min,检测波长214 nm,药物对映体得到良好分离。     

水溶性β-环糊精反应萃取分离苯基琥珀酸对映体的平衡研究

This paper deals with the enantioseparation of phenylsuccinic acid (H2A) enantiomers by liquid-liquid reactive extraction using β-CD derivatives as aqueous selectors. Cyclodextrin and its derivatives can interact with guest molecules selectively to form complexes with different stabilities. Cyclodextrin derivatives are not soluble in organic liquids, but highly soluble in water. In this work, hydroxypropyl-β-cyclodextrin (HP-β-CD), hydroxyethyl- β-cyclodextrin (HE-β-CD) and methyl-β-cyclodextrin (Me-β-CD) were selected as chiral selectors in aqueous phase for the reactive extraction of phenylsuccinic acid enantiomers from organic phase to aqueous phase. The results show that the efficiency of the extraction depends, often strongly, on a number of process variables, including the types of organic solvents and β-CD derivatives, the concentrations of the extractants and H2A enantiomers, pH and temperature. HP-β-CD, HE-β-CD and Me-β-CD have stronger recognition abilities for R-phenylsuccinic acid than for S-phenylsuccinic acid. Among the three kinds of β-CD derivatives, HP-β-CD has the strongest separation ability. Excellent enantio-separation was achieved under the optimal conditions of pH of 2.5 and temperature of 5°C with a maximum enantioselectivity (a) of 2.38. Reactive extraction of enantiomers with hydrophilic β-CD derivatives is of strong chiral separation ability and can be hopeful for separations of various enantiomers at a large-scale.     

Molecular Modeling Study of Chiral Separation and Recognition Mechanism of β-Adrenergic Antagonists by Capillary Electrophoresis

Chiral separations of five β-adrenergic antagonists (propranolol, esmolol, atenolol, metoprolol, and bisoprolol) were studied by capillary electrophoresis using six cyclodextrins (CDs) as the chiral selectors. Carboxymethylated-β-cyclodextrin (CM-β-CD) exhibited a higher enantioselectivity power compared to the other tested CDs. The influences of the concentration of CM-β-CD, buffer pH, buffer concentration, temperature, and applied voltage were investigated. The good chiral separation of five β-adrenergic antagonists was achieved using 50 mM Tris buffer at pH 4.0 containing 8 mM CM-β-CD with an applied voltage of 24 kV at 20 °C. In order to understand possible chiral recognition mechanisms of these racemates with CM-β-CD, host-guest binding procedures of CM-β-CD and these racemates were studied using the molecular docking software Autodock. The binding free energy was calculated using the Autodock semi-empirical binding free energy function. The results showed that the phenyl or naphthyl ring inserted in the hydrophobic cavity of CM-β-CD and the side chain was found to point out of the cyclodextrin rim. Hydrogen bonding between CM-β-CD and these racemates played an important role in the process of enantionseparation and a model of the hydrogen bonding interaction positions was constructed. The difference in hydrogen bonding formed with the -OH next to the chiral center of the analytes may help to increase chiral discrimination and gave rise to a bigger separation factor. In addition, the longer side chain in the hydrophobic phenyl ring of the enantiomer was not beneficial for enantioseparation and the chiral selectivity factor was found to correspond to the difference in binding free energy.