新型直链淀粉类手性固定相的制备与手性拆分性能

通过对糖单元2-位进行选择性酯化以及6-位保护与去保护,运用区域选择性方法合成了5种新型直链淀粉类衍生物,分别为直链淀粉-2-苯甲酸酯-3-(4-氯苯基氨基甲酸酯)-6-(3,5-二甲基苯基氨基甲酸酯)、直链淀粉-2-苯甲酸酯-3-(4-氯苯基氨基甲酸酯)-6-(3,5-二氯苯基氨基甲酸酯)、直链淀粉-2-苯甲酸酯-3,6-二(4-氯苯基氨基甲酸酯)、直链淀粉-2-(4-氯苯甲酸酯)-3,6-二(3,5-二氯苯基氨基甲酸酯)和直链淀粉-2-(4-氯苯甲酸酯)-3,6-二(环己基氨基甲酸酯),并将其涂覆在氨丙基硅胶表面制备了HPLC手性固定相。利用核磁共振-氢谱(¹H-NMR)和傅里叶变换红外光谱(FT-IR)技术对所合成衍生物的结构进行了表征和分析,并用HPLC法评价所合成衍生物的手性识别能力。与具有单一取代基直链淀粉类手性固定相的对比分析表明,所合成的新型直链淀粉类手性固定相对于某些对映体具有更为优异的拆分结果。进一步分析表明,2-、3-和6-位取代基的性能和引入位置对直链淀粉衍生物的手性识别能力均有较大的影响。     

High-performance liquid chromatography enantioseparation of proton pump inhibitors using the immobilized amylose-based Chiralpak IA chiral stationary phase in normal-phase, polar organic and reversed-phase conditions

The chiral resolving ability of the amylose-based Chiralpak IA chiral stationary phase towards omeprazole and other proton pump inhibitors under reversed-phase conditions was investigated. Organic modifier-buffer demonstrated to be a valid alternative elution mode with respect to conventional polar organic and normal-phases. No evidence of deterioration of performance of the enantioselective column after several multimodal cycles of elution was observed. Mobile phase composition was systematically changed in order to modulate the enantiomer elution order of set of compounds studied. A very simple method based on on-line detection of optical rotational sign during enantioselective HPLC was developed to assign the absolute configuration and enantiomeric elution order.     

高效液相色谱手性固定相法拆分阿折地平对映体

建立了阿折地平对映体的高效液相色谱拆分方法。采用Chiralpak AD-H (250 mm×4.6 mm, 5.0 μm, Daicel公司)手性色谱柱在正相条件下直接拆分阿折地平对映体,考察了固定相种类、流动相组成及柱温等对阿折地平对映体分离的影响。确定了最佳的拆分条件: 流动相为正己烷-异丙醇(90:10, v/v),流速为0.8 mL/min,检测波长为254 nm;柱温为20 ℃;在此条件下阿折地平对映体的分离度为3.3。该法简单快速,重现性好。     

高效液相色谱手性固定相法直接拆分外消旋雷诺嗪

在反相以及正相争件下，利用自制的涂敷型纤维素-三（3，5-二甲基苯基氨基甲酸酯）手性固定相直接拆分了外消旋雷诺嗪，并考察了不同流动相对手性拆分的影响，特别是醇类物质对拆分影响。结果表明，醇的立体结构、极性对雷诺嗪的手性拆分均有影响。实验结果显示无论在正相条件下还是在反相条件下，涂敷型纤维素-三（3，5-二甲基苯基氨基甲酸酯）手性固定相均可以很好的拆分外消旋体雷诺嗪。     

直链淀粉手性固定相拆分西那卡塞对映体

建立了一种快速、准确的高效液相色谱分析方法。使用Chiralpak AD-H手性色谱柱,检测波长224nm,考察了流动相中极性调节剂的体积分数、流动相中三乙胺的体积分数、柱温及流速对西那卡塞对映体拆分的影响。确立了最佳拆分条件:流动相为正己烷-异丙醇-三乙胺(90∶10∶0.1,V/V/V);流速为1.0 m L·min-1;柱温为30℃。在此优化实验条件下,得到西那卡塞对映体的出峰顺序为:先S体,后R体。所建立的方法简单准确,重复性好,可用于西那卡塞的质量研究和控制。     

纤维素手性固定相拆分阿替洛尔对映体

建立了阿替洛尔对映体的高效液相色谱分析方法。使用Chiralpak OD-H手性色谱柱,检测波长275nm。确定了最佳拆分条件:流动相为V(正己烷)∶V(异丙醇)∶V(三乙胺)=80∶20∶0.4;流速1.0 mL/min,柱温30℃。在该实验条件下,得到阿替洛尔对映体的出峰顺序为:先R体,后S体。所建立的方法简单准确,重复性好,可用于阿替洛尔的质量研究和控制。     

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。     

Analytical and semipreparative chiral separation of cis‐itraconazole on cellulose stationary phases by high‐performance liquid chromatography

cis‐Itraconazole is a chiral antifungal drug administered as a racemate. The knowledge of properties of individual cis‐itraconazole stereoisomers is vital information for medicine and biosciences as different stereoisomers of cis‐itraconazole may possess different affinity to certain biological pathways in the human body. For this purpose, either chiral synthesis of enantiomers or chiral separation of racemate can be used. This paper presents a two‐step high‐performance liquid chromatography approach for the semipreparative isolation of four stereoisomers (two enantiomeric pairs) of itraconazole using polysaccharide stationary phases and volatile organic mobile phases without additives in isocratic mode. The approach used involves the separation of the racemate into three fractions (i.e. two pure stereoisomers and one mixed fraction containing the remaining two stereoisomers) in the first run and consequent separation of the collected mixed fraction in the second one. For this purpose, combination of cellulose tris‐(4‐methylbenzoate) and cellulose tris‐(3,5‐dimehylphenylcarbamate) columns with complementary selectivity for cis‐itraconazole provided full separation of all four stereoisomers (with purity of each isomer > 97%). The stereoisomers were collected, their optical rotation determined and their identity confirmed based on the results of a previously published study. Pure separated stereoisomers are subjected to further biological studies.     

An amylopectin tris(phenylcarbamate) chiral stationary phase for high performance liquid chromatography

Amylopectin tris(phenylcarbamate) has been evaluated as a chiral stationary phase for HPLC; the influence on its cptical resolving capabilities of mobile phase composition and nature of the alcohol used as modifier has been studied. Separation and resolution of twelve arylalcohol racemates were examined. In most instances, the stationary phase exhibited high optical resolving capacity.     

纤维素衍生物手性固定相高效液相色谱法分离盐酸川丁特罗对映体

以纤维素三-(3,5-二甲基苯基氨基甲酸酯)为手性固定相(Lux Cellulose-1),建立了在正相色谱条件下直接分离盐酸川丁特罗对映体的高效液相色谱法。考察了乙醇、异丙醇等有机改性剂,三氟乙酸、二乙胺等流动相添加剂和柱温对对映体分离的影响。结果显示,酸性和碱性添加剂对对映体分离的影响最为显著: 添加二乙胺时两对映体无分离趋势;添加三氟乙酸时对映体保留强,且分离趋势明显;而同时添加三氟乙酸和二乙胺则两对映体分离显著改善,分离度可达4.0。优化后的色谱条件: 色谱柱为Lux Cellulose-1手性柱(250 mm×4.6 mm, 5 μm),流动相为正庚烷-乙醇-三氟乙酸-二乙胺(88:12:0.3:0.05, v/v/v/v),流速为1.0 mL/min,紫外检测波长为246 nm,柱温为25 ℃。该方法简便,快速,可用于左旋盐酸川丁特罗原料中右旋异构体杂质的检查。     

氟环唑外消旋体在纤维素-三(3,5-二甲基苯基氨基甲酸酯)手性固定相上的高效液相色谱法拆分

在纤维素-三(3,5-二甲基苯基氨基甲酸酯)（CDMPC）手性固定相上,分别采用正相、反相及极性有机相色谱模式对氟环唑外消旋体进行了拆分,并考察了流动相组成在手性识别中对手性分离的影响。氟环唑在Chiralcel OD-H手性色谱柱（填充CDMPC手性固定相）上采用反相色谱模式,以甲醇-水(体积比为80∶20)为流动相,获得了最佳的拆分,其两对对映异构体的分离度Rs分别为1.64和6.50。     

Analytical and semipreparative resolution of ranolazine enantiomers by liquid chromatography using polysaccharide chiral stationary phases

Novel HPLC methods were developed for the analytical and semipreparative resolution of new antianginal drug ranolazine enantiomers. Good baseline enantioseparation was achieved using cellulose tris (3,5-dimethylphenylcarbamate) (CDMPC) chiral stationary phases (CSPs) under both normal-phase and polar organic modes. The validation of the analytical methods including linearity, LODs, recovery, and precision, and the semipreparative resolution of ranolazine racemate were carried out using methanol as mobile phase without any basic and acidic additives under polar organic mode, using CDMPC CSPs. At analytical scale, the elution times of both enantiomers were less than 7.5 min at 20 degrees C and 1.0 mL/min, with the separation factor (a) 1.88 and the resolution factor (R(s)) 2.95. At semipreparative scale, about 14.3 mg/h enantiomers could be isolated and elution times of both enantiomers were less than 13 min at 2.0 mL/min. To increase the throughput, the technique of overlapping injections was used. The first eluted enantiomer was isolated with a purity of 99.6% enantiomer excess (e.e.) and > 99.0% yield. The second enantiomer was isolated with a purity of 98.8% e.e. and > 99.0% yield. In addition, optical rotation and circular dichroism spectroscopy of both ranolazine enantiomers isolated were also investigated.     

Enantioselective separation of indole derivatives by liquid chromatography using immobilized cellulose (3,5-dimethylphenylcarbamate) chiral stationary phase

A new chiral stationary phase of 3,5-dimethylphenylcarbamates of cellulose chemically bonded to 3-aminopropyl silica gel was prepared, which may be used with a wide range of solvents including standard and non-standard ones. Several racemic indole derivatives have been resolved using standard and non-standard solvents on the immobilized chiral column (15 cm × 0.46 cm) at a flow rate of 1.0 mL/min or 0.5 mL/min with a UV detection at 230 nm. Separation of indole derivatives on immobilized and coated chiral stationary phases (CSP) in HPLC using a mixture of hexane/2-propanol as mobile phase was compared. The resolution factors for immobilized and coated chiral column were 0.57–2.02 and 0.61–4.03, respectively. It was found that both coated and immbolized chiral stationary phases were suitable for the separation of indole derivatives; however, the coated CSP possesses a higher resolving power than the immobilized one. The article is published in the original.     

Evaluation of differences between Chiralpak IA and Chiralpak AD‐RH amylose‐based chiral stationary phases in reversed‐phase high‐performance liquid chromatography

Polysaccharide‐based chiral stationary phases can be used for the enantioselective separation of a wide range of structurally different compounds. These phases are available with chiral selectors coated or immobilized on silica gel support. The means of attachment of the chiral selector to the carrier can influence the separation performance of these stationary phases. This paper deals with evaluation of differences in the separation abilities of coated Chiralpak AD‐RH versus immobilized Chiralpak IA amylose‐based stationary phases in the reversed–phase mode of high–performance liquid chromatography. A set of chiral analytes was separated under acidic and basic conditions. Differences were observed in the enantioseparation potential of the tested phases. The linear‐free energy relationship and additional evaluation of ionic interactions were used to ascertain whether the interactions that participate in retention and enantioseparation are affected by the means of preparation of these phases. All the interactions covered by the linear‐free energy relationship were significant for the studied phases and their absolute values were almost always higher for the coated phase. Ionic interactions were found to be more important on the immobilized stationary phase but did not contribute to any improvement in the enantioselective separation performance.     

Preparation and chiral separation of a novel immobilized cellulose-based chiral stationary phase in high-performance liquid chromatography

The chiral selector 6-azido-2, 3-di(p-chlorophenylcarbamoylated) cellulose was synthesized and further chemically immobilized onto 5-μm amino functionalized spherical porous silica gel. It was used as chiral stationary phase in high-performance liquid chromatography. Thirty racemates were successfully separated into enantiomers in either normal phase mode or reversed-phase mode. Good reproducibility and stability of the chiral stationary phase have been demonstrated.     

Per(3-chloro-4-methyl)phenylcarbamate cyclodextrin clicked stationary phase for chiral separation in multiple modes high-performance liquid chromatography

In this work, a detail study has been performed on the enantioselectivity of per(3-chloro-4-methyl)phenylcarbamate-β-CD clicked chiral stationary phase (CSP) in high-performance liquid chromatography. Both normal phase and polar organic mobile phases have been explored for the enantioseparation of 39 model racemic pairs including aromatic alcohols, flavonoids, β-blockers and amino acids. Chiral resolution values over 10 were achieved for flavonoids. The comparison study with reference perphenylcarbamate-β-CD clicked CSP reveals the significance of 3-chloro-4-methyl functionality in improving the enantioselectivities. This study may provide insight on the multiple interactions between functionalized CD and analytes.     

Dipyridine modified silica--a novel multi-interaction stationary phase for high performance liquid chromatography

A novel multi-interaction stationary phase based on 4,4'-dipyridine modified silica was synthesized and characterized, by infrared spectra, X-ray photoelectron spectroscopy and elemental analysis. Mechanism involved in the chromatographic separation is the multi-interaction including π-π, hydrophobic, hydrogen-bonding, electrostatic and anion-exchange interactions. Based on these interactions, polycyclic aromatic hydrocarbons and phenols were successfully separated respectively in reversed-phase chromatography; inorganic and organic anions were also separated individually in anion-exchange chromatography by using the same column. Furthermore, the simultaneous separation of neutral organics, inorganic and organic anions was obtained on this stationary phase with the appropriate mobile phase. Therefore, such stationary phase has the characteristics of multi-interaction mechanism and multi-modal separation, and has potential application on complex samples.