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排序方式: 共有231条查询结果,搜索用时 15 毫秒
1.
Numerous chemical compounds of high practical importance, such as drugs, fertilizers, and food additives are being commercialized as racemic mixtures, although in most cases only one of the isomers possesses the desirable properties. As our understanding of the biological actions of chiral compounds has improved, the investigation of the pharmacological and toxicological properties has become more and more important. Chirality has become a major issue in the pharmaceutical industry; therefore, there is a continuous demand to extend the available analytical methods for enantiomeric separations and enhance their efficiency. Direct liquid chromatography methods based on the application of chiral stationary phases have become a very sophisticated field of enantiomeric separations by now. Hundreds of chiral stationary phases have been commercialized so far. Among these, macrocyclic glycopeptide-based chiral selectors have proved to be an exceptionally useful class of chiral selectors for the separation of enantiomers of biological and pharmacological importance. This review focuses on direct liquid chromatography-based enantiomer separations, applying macrocyclic glycopeptide-based chiral selectors. Special attention is paid to the characterization of the physico-chemical properties of these macrocyclic glycopeptide antibiotics providing detailed information on their applications published recently. 相似文献
2.
Kenan Can Tok Mehmet Gumustas Giorgi Jibuti Halit Sinan Suzen Sibel A. Ozkan Bezhan Chankvetadze 《Molecules (Basel, Switzerland)》2020,25(24)
In a recent study, opposite enantiomer elution order was observed for ketoprofen enantiomers on two amylose-phenylcarbamate-based chiral columns with the same chemical composition of the chiral selector but in one case with coated while in the other with an immobilized chiral selector. In the present study, the influence of this uncommon effect on method validation parameters for the determination of minor enantiomeric impurity in dexketoprofen was studied. The validated methods with two alternative elution orders for enantiomers were applied for the evaluation of enantiomeric impurity in six marketed dexketoprofen formulations from various vendors. In most of these formulations except one the content of enantiomeric impurity exceeded 0.1% (w/w). 相似文献
3.
Marta Colombo Rosella Ferretti Leo Zanitti Roberto Cirilli 《Journal of separation science》2020,43(13):2589-2593
Ramosetron is an enantiopure active pharmaceutical ingredient marketed in Japan since 1996 and later in a few Southeast Asian countries predominantly as an antiemetic for patients receiving chemotherapy. In this study, a simple and rapid high‐performance liquid chromoatography method for the separation of ramosetron and its related enantiomeric impurity by using hydrophilic interaction liquid chromatography mode is presented. Chiral resolution was performed on an analytical column (100 mm × 4.6 mm id) packed with 3 μm particles of cellulose‐based Chiralpak IC‐3 chiral stationary phase. Using a mobile phase containing acetonitrile–water–diethylamine (100:10:0.1, v/v/v) and setting the column temperature at 35°C, the resolution value was 7.35. At a flow rate of 1 mL/min, the enantioseparation was completed within 5 min. The proposed method was partially validated and it has proven to be sensitive with limit of detection and limit of quantitation of the (S)‐enantiomer impurity of 44.5 and 133.6 ng/mL. 相似文献
4.
Ann Gogolashvili Lali Chankvetadze Nino Takaishvili Antonio Salgado Bezhan Chankvetadze 《Electrophoresis》2020,41(12):1023-1030
The major goal of this study was to determine the affinity pattern of the terbutaline (TB) enantiomers toward α-, β-, γ-, and heptakis(2,3-di-O-acetyl)-β-cyclodextrins and using NMR spectroscopy for the understanding of the fine mechanisms of interaction between the cyclodextrins (CD) and TB enantiomers. It was shown once again that CE in combination with NMR spectroscopy represents a sensitive tool to study the affinity patterns and structure of CD complexes with chiral guests. Opposite affinity patterns of TB enantiomers toward native α- and β-CDs were associated with significant differences between the structure of the related complexes in solution. In particular, the complex between TB enantiomers and α-CD was of the external type, whereas an inclusion complex was formed between TB enantiomers and β-CD. One of the possible structures of the complex between TB and heptakis(2,3-di-O-acetyl)-β-CD (HDA-β-CD) was quite similar to that of TB and β-CD, although the chiral recognition pattern and enantioselectivity of TB complexation with these two CDs were very different. 相似文献
5.
采用高效液相色谱法,以9-蒽醛为衍生试剂,在5种多糖衍生物的手性固定相(CSPs)上对几种α-氨基酸甲酯对映体进行了手性分离。色谱条件如下: 流动相为含3%~10%(v/v)异丙醇的正己烷溶液,流速为1.0 mL/min,检测波长为254 nm。结果表明,α-氨基酸甲酯-9-蒽醛亚胺衍生物在Chiralcel OD柱或Chiralcel OD-H柱上的手性分离结果优于其他CSPs,而且在Chiralcel OD柱或Chiralcel OD-H柱上全部得到了基线拆分(α=1.24~5.47, Rs=2.56~13.90), L-对映体在这两种色谱柱上的保留强于D-对映体。同时还考察了几种脂肪胺在5种多糖衍生物手性固定相上的对映体拆分效果,结果表明脂肪胺的9-蒽醛亚胺衍生物在Chiralcel OD柱或Chiralcel OD-H柱上的分离效果良好。该法可用于其他α-氨基酸酯和胺类化合物对映体的分析。 相似文献
6.
Qiuyun Wang Yajin Xiong Baozhu Lu Jun Fan Sheng Zhang Shengrun Zheng Weiguang Zhang 《Journal of separation science》2013,36(8):1343-1348
N‐(2,4‐dinitrophenyl)‐proline and N‐(2,4‐dinitrophenyl)‐serine were enantiomerically resolved on the BSA chiral stationary phase by HPLC in reversed‐phase mode. Effects of chromatographic conditions on enantioseparation and elution order have been investigated in detail. For these two samples, reversal of enantiomer elution order was observed by changing buffer pH, the content of acetonitrile, or alcohol modifiers in mobile phase, which is firstly reported in the BSA chiral stationary phase studies. More interestingly, combined effect between buffer pH and the content of acetonitrile was also observed. In addition, coelution range of enantiomers varied along with the content of acetonitrile in mobile phase. 相似文献
7.
8.
9.
Fahimeh Sabbaghi Mehrdad Pourayoubi Marek Ne
as Krishnan Damodaran 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(1):77-84
The crystal structures of two single‐enantiomer amidophosphoesters with an (O)2P(O)(N) skeleton, i.e. diphenyl [(R)‐(+)‐α‐methylbenzylamido]phosphate, (I), and diphenyl [(S)‐(?)‐α‐methylbenzylamido]phosphate, (II), both C20H20NO3P, are reported. In both structures, chiral one‐dimensional hydrogen‐bonded architectures, along [010], are mediated by N—H…OP interactions. The statistically identical assemblies include the noncentrosymmetric graph‐set motif C(4) and the compounds crystallize in the chiral space group P21. As a result of synergistic co‐operation from C—H…O interactions, a two‐dimensional superstructure is built including a noncentrosymmetric R44(22) hydrogen‐bonded motif. A Cambridge Structural Database survey was performed on (O)2P(O)(N)‐based structures in order to review the frequency of space groups observed in this family of compounds; the hydrogen‐bond motifs in structures with chiral space groups and the types of groups inducing chirality are discussed. The 2,3JX–P (X = H or C) coupling constants from the NMR spectra of (I) and (II) have been studied. In each compound, the two diastereotopic C6H5O groups are different, which is reflected in the different chemical shifts and some coupling constants. 相似文献
10.
基于联萘衍生物手性构型高度稳定以及联萘结构中2个萘平面的两面角可以在一定范围内张合的特点, 分别以光学活性的(R)和(S)-2,2'-二乙炔基-1,1'-联萘为模板, 设计了一种含有8个“铰链”结构单元的新的环芳分子¾—(R,R,R,R,R,R,R,R)-3和(S,S,S,S,S,S,S,S)-3. 其合成路线涉及间苯基连接桥的链接, 保护基的脱去和控制导入以及分子间偶合等步骤. 用MS, IR, UV-Vis, 1H和13C NMR以及元素分析等技术对中间体和目标化合物进行了结构表征. 测定并比较了2个目标化合物的比旋光度[α]D和圆二色(CD)性质. 在CH2Cl2溶液中, 两个异构体(R,R,R,R,R,R,R,R)-3和(S,S,S,S,S,S,S,S)-3的[α]D25值分别为-911.8和+908.6, 并且它们的CD谱表现出对称的镜像特征.这些实验结果清楚地反映了它们之间的对映异构关系. 相似文献