The study of chiral discrimination of organophosphonate derivatives on pirkle type chiral stationary phase by molecular modeling

Molecular modeling and molecular dynamics (MD) have been used to study the chiral discrimination and interaction energy of organophosphonate in N-(3,5-dinitrobenzoyl)-S-leucine chiral stationary phase (CSP). The elution order of the enantiomers can be predicted from the interaction energy. Quantitative structure-retention relationship (QSRR) has also been used as an alternative method to confirm the elution order of enantiomers. Molecular mechanics (MM), molecular dynamics and QSRR proved to be useful methods to study chiral discrimination.     

反相液相色谱法分离2-(4-羟基苯氧基)丙酸酯对映体

合成了三-(4-甲基苯甲酸)纤维素酯(MCTB)手性固定相，用反相高效液相色谱法在该手性固定相上对2-(4-羟基苯氧基)丙酸酯对映体进行拆分．实验结果表明，在三-(4-甲基苯甲酸)纤维素酯手性固定相上，以甲醇与水的体积分数为75：25做流动相能较好的拆分2-(4-羟基苯氧基)丙酸甲酯、乙酯和丁酯对映体，其分离因子分别为1．38、1．49、0．98；同时还发现2-(4-羟基苯氧基)丙酸酯中酯基团的大小对其对映体的分离也有明显的影响，其中以乙酯的拆分效果最佳。     

直链淀粉手性固定相高效液相色谱法拆分比索洛尔对映体

采用直链淀粉手性固定相高效液相色谱法在正相条件下直接拆分了比索洛尔对映异构体。分别以异丙醇、乙醇为有机改性剂,考察了流动相的组成与配比、流速及柱温等因素对比索洛尔对映体分离的影响。确定了比索洛尔对映体的最佳拆分条件:流动相正己烷-乙醇-二乙胺(体积比为88∶12∶0.1),流速0.6 mL/min,检测波长270 nm,柱温20 ℃。该方法可快捷、简便地拆分比索洛尔对映体。     

N-(2-甲基-6-乙基苯基)丙氨酸对映体的毛细管电泳分离

采用高效毛细管区带电泳法,以β-环糊精及其衍生物作为手性选择剂,对外消旋N-(2-甲基-6-乙基苯基)丙氨酸(EMPA)的两个对映体进行了手性分离,比较了环糊精种类、环糊精浓度、电解质溶液pH值、温度和电场强度对分离的影响.实验结果表明,采用2,6-O-二甲基-β-环糊精为手性选择试剂,环糊精浓度为40mmol/L、电解质溶液pH=5.5及温度为20℃时分离效果最佳,对映体基本达基线分离,线性范围为20～200mg/L,最低检测限为10mg/L.     

衍生化环糊精键合固定相对N-苄氧甲酰基-α-氨基膦 酸酯化合物色谱保留和手 性识别机理的研究

正相条件下,一系列N-苄氧甲酰基-α-氨基膦酸二苯酯化合物首次在苯基氨基甲酸酯衍生化β环糊精键合硅胶固定相上实现了高效液相色谱手性拆分,结合热力学模型,对手性分离过程的热力学行为进行了讨论。探索运用定量结构-对映异构体选择性保留关系的方法,将对映异构体的色谱保留和溶质分子描述参数相关性闻系建立定量方程,从超热力学模型的角度研究了色谱保留和手性识别机理。     

Direct chiral high performance liquid chromatography separation of O-ethyl O-phenylN - isopropylphosphoroamidothioates

The enantiomers of thirty-nine O-ethyl O-phenyl N-isopropyl phosphoroamidothioates have been separated by high performance liquid chromatography on a Pirkle model chiral stationary phase using ten mobile phase. Chromatographic data are presented for the separation of these organic phosphorus enantiomers on the chiral phase. The influences of molecular structures and compositions of mobile phases have been described.     

Analytic and preparative resolution of recemic γ- and δ-lactones by chromatography on cellulose triacetate. Relationship between elution order and absolute configuration

Enantiomers of various chiral five- and six-membered-ring lactones, Which are important classes of compounds (flavour and Pheromone components, key intermediates in the synthesis of biologically active substances) have been separated chromatographically on the chiral phase cellulose triacetate, crystallographic form I (CTAI). For different series of five-membered-ring lactones, relationships have been found between the elution order of the enantiomers and their absolute configuration. Preparative resolutions of γ-Phenyl-γ-butyrolactone ( 1 ) and of the Pheromone component 5b have been carried out to demonstrate the applicability of the method to g-scale separations.     

Resolution and chiroptical properties of the neurotoxin 1-trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo) and related compounds: quantum chemical CD calculations and X-ray diffraction analysis

Separation and stereochemical attribution of the two enantiomers of the neurotoxin 1-trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo) has been achieved by applying chromatography on a chiral phase HPLC column in hyphenation with circular dichroism (CD) spectroscopy (LC-CD coupling). Assignment of the absolute configuration of TaClo and its N-methyl analog has been achieved by quantum chemical CD calculations and has finally been confirmed by single-crystal X-ray diffraction analyses of the two enantiomers of N-formyl-TaClo as obtained in enantiomerically pure form by crystallization.     

Enantioselective separation of all-E-astaxanthin and its determination in microbial sources

A method for the enantioselective separation of all-E-astaxanthin (3,3'-dihydroxy-beta,beta-carotene-4,4'-dione), an important colorant in the feed industry, was developed. Different chiral stationary phases (CSPs) such as Pirkle phases (R,R Ulmo and l-leucine), modified polysaccharides and a beta-cyclodextrin have been investigated on their separation performance of astaxanthin enantiomers. Direct resolution was only achieved employing the Chiralcel OD-RH (cellulose-tris-3,5-dimethylphenyl-carbamate) under reversed phase conditions. The chiral separation of the enantiomeric forms of astaxanthin produced in microalgae and yeasts was reported. The yeast Xanthophyllomyces sp. produces astaxanthin predominantly in the R,R configuration, whereas in the green microalgae Scenedesmus sp. astaxanthin is built primarily in the S,S form. The separation method for the identification of astaxanthin enantiomers is of great interest since astaxanthin is used as functional food additive in human nutrition. Moreover the method may be used as a food chain indicator in farmed salmon.     

基于直链淀粉衍生物手性固定相的高效液相色谱-串联质谱法拆分4种β-受体阻滞剂对映体及其分离机制的探讨

建立了以直链淀粉衍生物为手性固定相的高效液相色谱-串联质谱(HPLC-MS/MS)直接拆分普萘洛尔、美托洛尔、阿罗洛尔和卡维地洛4种β-受体阻滞剂对映体的方法。考察了手性固定相的种类、流动相改性剂和添加剂的体积分数、柱温和流速等对4种药物对映体分离的影响。结果表明:在Chiralpak AD-H手性色谱柱上,在正己烷-乙醇-二乙胺(20∶80∶0.03,v/v/v)为流动相、流速0.550 mL/min、柱温40℃的条件下,普萘洛尔、美托洛尔、阿罗洛尔和卡维地洛对映体均达到基线分离,分离度分别为1.37、1.80、2.09和4.70。通过热力学研究及对映体结构分析对拆分机理进行了探讨,发现4种药物对映体的手性拆分均为焓驱动过程,而固定相的手性空腔对不同药物的拆分影响较大。研究结果为β-受体阻滞剂的深入研究提供了参考方法。     

Enantioselective resolution of chiral aromatic acids by biphasic recognition chiral extraction

This paper reports a new chiral separation technology—biphasic recognition chiral extraction for the separation of aromatic acid enantiomers such as α-cyclohexyl-mandelic acid (CHMA) and naproxen (NAP). The biphasic recognition chiral extraction system was established by adding hydrophobic d(l)-isobutyl tartrate in 1,2-dichloroethane organic phase and hydrophilic β-cyclodextrin (β-CD) derivative in aqueous phase, which preferentially recognize the (R)-enantiomer and (S)-enantiomer, respectively. These studies involve an enantioselective extraction in a biphasic system, where aromatic acid enantiomers form complexes with the β-cyclodextrin derivative in the aqueous phase and d(l)-isobutyl tartrate in the organic phase, respectively. Factors affecting the extraction mechanism are analyzed, namely the influence of the concentrations of the extractants and aromatic acid enantiomers, the types of the extractants, pH, and temperature. The experimental results show that the biphasic recognition chiral extraction is of much stronger chiral separation ability than the monophasic recognition chiral extraction, which utilizes the cooperations of the forces of the tartrate and the β-CD derivative. Hydroxypropyl-β-cyclodextrin (HP-β-CD), hydroxyethyl-β-cyclodextrin (HE-β-CD), and methyl-β-cyclodextrin (ME-β-CD) have stronger recognition abilities for the (S)-aromatic acid enantiomers than those for (R)-aromatic acid enantiomers, among which HP-β-CD has the strongest ability. d-Isobutyl tartrate preferentially recognizes (R)-CHMA and (S)-NAP, while l-isobutyl tartrate preferentially recognizes (S)-CHMA and (R)-NAP. The maximum enantioselectivities of CHMA and NAP are 2.49 and 1.65, under conditions at which the pH values of the aqueous phases are 2.7 and 2.5, at the ratio of 2:1 of [isobutyl tartrate] to [HP-β-CD].     

衍生化β-环糊精手性固定相高效液相色谱法拆分米那普仑对映体及其分离机制

建立了新型抗抑郁药米那普仑在环糊精手性固定相上的高效液相色谱拆分方法。在反相色谱条件下采用未衍生化β-环糊精(Cyclobond I 2000)、乙酰基-β-环糊精(AC-β-CD)、2,3-二甲基-β-环糊精(DM-β-CD)、3,5-二甲基苯基氨基甲酸酯-β-环糊精(DMP-β-CD)4种手性柱分离米那普仑对映体。考察了固定相、流动相比例、pH、流速和柱温对拆分的影响。利用分子对接和结合能计算方法,研究米那普仑分子与AC-β-CD的对接过程,探讨其可能的分离机制。优化后的拆分条件如下:固定相为乙酰基-β-环糊精手性柱Astec CYCLOBONDTMI 2000 AC(25 cm×4.6 mm,5μm),流动相为乙腈-0.1%(体积分数)pH 5.0醋酸三乙胺溶液(TEAA)(5∶95,v/v),流速为0.4mL/min,柱温为25℃,检测波长为220 nm。在此条件下,米那普仑对映体获得快速拆分,分离度(Rs)为1.74,理论塔板数为10 125。分子模拟结果表明引起手性识别的作用力主要是环糊精衍生化的乙酰基导致的氢键作用差异。该方法快速、高效、重现性好。     

高效液相色谱手性流动相添加法拆分奥昔布宁对映体

采用C18固定相,以羟丙基-β-环糊精为手性流动相添加剂,建立了奥昔布宁对映体的高效液相色谱拆分方法。考察了手性添加剂、有机极性调节剂、缓冲盐的种类和浓度以及流动相的pH值和流速及柱温等因素对对映体分离的影响。在最佳分离条件下,奥昔布宁对映体的分离度为1.54,检测限为1.0 ng。该方法简便,重复性好,比手性固定相法更加经济。     

Direct optical resolution of the enantiomers of axially chiral compounds by high-performance liquid chromatography on cellulose tris-(3,5-dimethylphenylcarbamate) stationary phase

Summary The enantiomeric separation of nineteen biphenyl dimethyl dicarboxylate derivatives has been examined by HPLC on a chiral statonary phase prepared by coating aminopropylated silica gel with cellulose tris-(3,5-dimethylphenylcarbamate). It was found that trifluoroacetic acid (TFA) has a dominant effect on chiral separation for acidic compounds. The percentage of 2-propanol in the mobile phase does not have a large effect on the anantioselectivity but the separation was dramatically influenced by the kind of alcohol in the mobile phase. The effect of temperature on the chiral separation is also discussed. Most of the enantiomers investigated could be resolved satisfactorily.     

手性有序无机介孔硅用作气相色谱固定相

手性介孔材料在手性分离、不对称催化、手性传感等领域具有广泛的应用价值。手性有序无机介孔硅是一类介孔结构高度有序、不含有机成分的手性材料。该文采用D-苯丙氨酸为手性源合成手性有序无机介孔硅(COIMS),将其用聚硅氧烷(OV-1701)稀释后用作固定相制备毛细管气相色谱手性柱,并对该手性柱的分离性能进行了考察,8种手性化合物在该手性柱上得到了拆分。COIMS柱对直链烷烃、醇的分离也表现出良好的选择性。该柱还具有分析时间短、在较高温度下测定稳定等优点,其具有开发成高温手性固定相的潜力。     

几种苯甲酰胺类抗精神病药物的手性色谱拆分及其对映体含量的测定

采用直链淀粉-三(5-氯-2-甲基苯基氨基甲酸酯)手性固定相(CSP),以0.1%二乙胺正己烷和0.1%二乙胺乙醇为流动相梯度洗脱,以舒必利、阿米舒必利和莫沙必利为目标物,利用高效液相色谱法研究了这3种苯甲酰胺类药物的手性色谱分离行为。分别考察了流动相组成、添加剂及柱温对3种药物对映体分离的影响,从热力学和结构上探讨了色谱拆分的机理。结果表明: 在优化的色谱条件下,舒必利、阿米舒必利和莫沙必利对映体的分离度Rs＞1.5;计算了3种药物对映体的色谱保留因子k和分离因子α,以及与CSP相互作用的热力学函数,其相互作用大小依次为舒必利＞阿米舒必利＞莫沙必利。已将该方法成功地应用于上述3种药物片剂和血清中其对映体的测定,方法简便、准确、可靠。     

氨基酸衍生物对映体的高效液相色谱手性分离

通过在流动相中使用酸性添加剂,在由(S)-N-(2-萘基)丙氨酸衍生而成的手性固定相上直接分离氨基酸的3,5-二硝基苯甲酰衍生物,获得非常理想的分离效果。并在此工作的基础上对手性识别机理进行了初步探讨。另外,通过在不同构型的手性固定相上分离相同的溶质,证明在结构相同、构型相反的手性固定相上,对映体的出峰顺序是相反的。     

安非他明类毒品的手性对映体气相色谱-质谱分析

采用手性衍生化试剂：（S）（－）N－三氟乙酰－1－脯胺酰氯（TPC）和（R）（＋）－α-甲氧基－α－三氟甲基苯乙酸（MTPA）与安非他明类对映体衍生化产物,通过常规的GC／MS方法将其分离,本文较系统地考察了这两种手性试剂衍生化反应中溶剂、手性试剂用量、加热温度、反应时间等因素对安非他明类在体衍生化结果的影响。实现了Am、MAm、MDA、MDMA、MDEA、MBDB等几种毒品对映体间的良好分离。