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1.
右旋邻氯扁桃酸分子印迹聚合物的制备及结合特性研究 总被引:6,自引:0,他引:6
以右旋邻氯扁桃酸为模板分子合成了具有高选择性的分子印迹聚合物作为手性分离材料 .紫外光谱研究说明在聚合开始之前模板分子与功能单体形成了配合物 ,并用Hyperchem软件模拟其分子结构 ,结合能分别为 -1 643 7× 1 0 4 J·mol- 1 和 -4 2 799× 1 0 4 J·mol- 1 .分子印迹聚合物对模板分子的结合量高于其它类似物 ,手性分离因子α达 1 76.Scatchard分析表明分子印迹聚合物在识别右旋邻氯扁桃酸分子过程中存在两类结合位点 ,与配合物模拟结构数目一致 相似文献
2.
以混旋邻氯扁桃酸为模板的分子印迹聚合物的制备及拆分性能研究 总被引:6,自引:0,他引:6
以混旋邻氯扁桃酸为模板分子和合成的(S)-(1-萘乙基)-丙烯酰胺为手性功能 单体制备分子印迹聚合物作为色谱固定相,对混旋邻氯扁桃酸有较好的拆分能力, 分离因子α达到1.36。但对模板分子的类似物混旋扁桃酸和对氯扁桃酸没有拆分能 力。用Hyperchem软件模拟了(S)-邻氯扁桃酸与(S)-(1-萘乙基)-丙烯酰胺形成的复 合物的结构模型,其在聚合物母体中留下的具有立体构型和作用力双重识别的S-S 型空穴,对(S)-邻氯扁桃酸有较强的保留作用,从而达到对混旋物拆分的目的。 相似文献
3.
高效液相色谱手性流动相添加剂法分离扁桃酸和邻氯扁桃酸对映体 总被引:8,自引:0,他引:8
扁桃酸和邻氯扁桃酸是医药生产中的重要中间体。以氨基酸和金属离子作为手性流动相添加剂的配体交换色谱已被广泛应用于手性物质分离,但用于拆分扁桃酸较难,因其紫外吸收波长短,而使用最常用的Cu^2 作为配合离子时有很强的紫外吸收。本实验采用Zn^2 作配合离子,避开了检测方面的难题,直接拆分了扁桃酸和邻氯扁桃酸对映体。 相似文献
4.
对比了商品化的淀粉型手性固定相Chiralcel OJ-H和纤维素型手性固定相Chiralpak AD-H柱在正相条件下对扁桃酸系列8个化合物的拆分,结果表明Chiralcel OJ-H柱对扁桃酸系列化合物具有更强的手性识别能力,8个外消旋扁桃酸化合物在36 min内都得到了基线分离。研究发现,扁桃酸苯环上的取代基对其拆分的难易程度影响很大,其电子诱导效应影响扁桃酸类化合物在固定相上的保留时间,其空间位阻效应是扁桃酸在固定相上被拆分成败的决定因素。通过对比分析扁桃酸和手性柱的结构,探讨了可能的手性拆分机理是基于Chiralpak AD-H(Chiralcel OJ-H)手性固定相和扁桃酸系列化合物之间的氢键-氢键、偶极-偶极、π-π电子相互作用以及空间适应性等诸多因素的综合影响,其中空间适应性起到至关重要的作用。本研究可为一些实际光学活性扁桃酸及其类似物的对映体纯度测定与拆分研究提供参考。 相似文献
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2,6-二-O-戊基-β-环糊精涂渍Symmetry C8柱拆分扁桃酸及其类似物对映体 总被引:4,自引:0,他引:4
利用合成的2,6-二-O-戊基-β-环糊精涂渍Symmetry C8色谱柱,研究了扁桃酸及其类似物等6
种外消旋对映体的反相高效液相色谱拆分。优化了色谱分离条件,探讨了扁桃酸的手性拆分机理。结果表明,采用优化后的甲醇-水或甲醇-0.5%三乙胺-乙酸缓冲液流动相等色谱条件,扁桃酸、扁桃酸甲酯、苯基甘氨酸、苯基琥珀酸和安息香等5种外消旋对映体达到或接近基线分离,其中前4种对映体均为(S)-构型先出峰。该法可用于实际样品的对映体纯度测定。 相似文献
7.
该文合成了一种具有三维钻石网络状通道的单一手性POC材料(CC3-R),将其用作手性固定相制备CC3-R毛细管电色谱柱,考察了其手性识别性能,并测试了电流随电压的变化及电渗流随缓冲溶液pH值的变化,然后以该柱对扁桃酸进行了拆分。结果显示,D-扁桃酸和L-扁桃酸得到了基线分离,分离度为1.81,理论塔板数分别为36 700 N/m和41 600 N/m,同一根CC3-R毛细管电色谱柱对扁桃酸的保留时间的相对标准偏差为1.2%。表明CC3-R手性柱不仅有良好的手性识别能力还具有良好的稳定性和重现性。 相似文献
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提出一种新的手性分离技术双相(O/W)识别手性萃取. 研究了α-环己基扁桃酸对映体在D(L)-酒石酸异丁酯1,2-二氯乙烷有机相和β-环糊精衍生物水相萃取体系中的分配行为; 考察了β-环糊精衍生物种类和浓度、酒石酸酯构型和浓度、水相pH 值等因素对萃取性能的影响. 实验结果表明, 双相(O/W)识别手性萃取具有很强的手性分离能力, 羟丙基β-环糊精、羟乙基β-环糊精、甲基β-环糊精均对S-α-环己基扁桃酸对映体的识别能力大于对R-α-环己基扁桃酸对映体的识别能力, 其中以羟丙基β-环糊精的识别能力最强; 而D-酒石酸异丁酯的识别能力刚好相反; 在羟丙基β-环糊精和D-酒石酸异丁酯萃取体系中, α-环己基扁桃酸外消旋体一次萃取分离后, 水相中S-对映体e.e.%达到27.6%, R-和S-对映体的分配系数(kR和kS)分别为2.44和0.98, 分离因子(α)达2.49; 同时pH值和萃取剂浓度对手性分离能力有显著影响. 双相(O/W)识别手性萃取对外消旋体化合物的制备性分离有着十分重要的意义. 相似文献
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N. Dimov 《Chromatographia》1999,50(1-2):61-64
Summary The liquid-chromatographic separation of the enantiomers of amino acid esters as benzophenone Schiff-base derivatives on polysaccharide-derived
chiral stationary phases (CSPs) is described. The performance of Chiralcel OF was superior to that of the other CSPs for resolution
of benzophenone imine derivatives of amino acid ethyl and methyl esters. The enantiomers of most of the amino acid esters
examined as their benzophenone imine derivatives were resolved to baseline on Chiralcel OF. The L-(−) enantiomers of all the
analytes were preferentially retained on Chiralcel OF. The resolution of several imine derivatives of amino acid esters was
investigated, as was the effect of eluent composition on the resolution of amino acid ethyl esters as their benzophenone imine
derivatives. 相似文献
12.
The carbobenzyloxy (cbz) protecting group is evaluated for it's potential to enhance the resolution of chiral amine enantiomers using high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). A series of cbz derivatives of commercially available racemates was prepared and analyzed by enantioselective chromatography using a variety of mobile phases and polysaccharide and Pirkle-type chiral stationary phases (CSPs). The cbz-derivatized product consistently demonstrated enhanced chiral resolution under HPLC and SFC conditions. Improved selectivity and resolution combined with an automated preparative HPLC or SFC system can lead to the rapid generation of highly purified enantiomers of desirable starting materials, intermediates or final products. 相似文献
13.
Xing Juan Chen Guang Lei Yang Jin Jin Sheng Jun Shen Hong Xing Dong 《液相色谱法及相关技术杂志》2016,39(14):647-657
Five β-cyclodextrin (β-CD) derivatives bearing substituted phenylcarbamate/3-(triethoxysilyl)propylcarbamate groups at the 2-, 3-, and 6-positions of glucose unit and another five derivatives containing benzoate at the 2-position and substituted phenylcarbamate/3-(triethoxysilyl)propylcarbamate groups at the 3- and 6-positions were synthesized using the regioselective esterification method. The obtained β-CD derivatives were efficiently immobilized onto the silica gel through the intermolecular polycondensation of a small amount of the triethoxysilyl groups, which were used as the chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). The chiral separation properties of these CSPs were evaluated under the normal-phase HPLC. The effects of solvent polarity and the side chain structures of β-CD derivatives on the chiral recognition ability of the immobilized CSPs were investigated. Among these β-CD derivative CSPs, 2,3,6-tris(3,5-dichlorophenylcarbamate)-β-CD CSP showed a relatively high chiral recognition ability for the studied racemates. The regioselective esterification at the 2-position of glucose unit in the β-CD decreased the chiral recognition ability at the same conditions. For some racemates, the β-CD derivative CSPs showed chiral recognition abilities comparable or better to some chemical bonded β-CD derivative CSPs and 3,5-dichloro- and 3,5-dimethylphenylcarbamates of cellulose and amylose CSPs. 相似文献
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Thin-layer chromatography (TLC) based on molecularly imprinted polymers (MIPs) of alpha-agonists as chiral stationary phases was applied to the determination of enantiomers of various adrenergic drugs including alpha- and beta-agonists and beta-antagonists (beta-blockers). In this study, three MIPs imprinted with (+)-ephedrine, (+)-pseudoephedrine and (+)-norephedrine plus a non-imprinted polymer (non-MIP) were prepared, processed and coated on a glass support as thin layers. then enantiomeric determination of adrenergic drugs was carried out by development of their racemates on the TLC plates, using established conditions. From the results, the racemates of the compounds used as print molecules were well separated into two isomers on the MIP-plates, except on the plate based on MIP of (+)-norephedrine. Most adrenergic drugs structurally related to print molecules were completely resolved into two spots with the MIP plates. In general the retention of (+)-isomers (or 1S-isomers) was greater than that of (-)-isomers (or 1R-isomers), indicating the stereoselectivity of the MIPs with the former isomers. Moreover, the role between the chemical structures of the analytes with chiral recognition of the MIPs has been investigated. The proposed method enables rapid determination of enantiomers and screening of large numbers for optical purity of adrenergic drugs. 相似文献
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Impregnated silica TLC plates with L-(-)-serine and L-(-)-threonine and a mixture of L-(-)-serine and L-(-)-threonine (1:1) as chiral selectors were prepared to use as chiral stationary phases (CSPs) in thin layer chromatography. The resolution of the enantiomers of 2-arylpropionic drugs, including ibuprofen, ibuproxam, ketoprofen, pranoprofen, benoxaprofen, flurbiprofen and tiaprofenic acid was investigated on these CSPs. A mobile phase system of acetonitrile-methanol-water (16:4:0.5, v/v/v) was used. The spots were detected with iodine vapours and the detection limits were found to range between 0.25 and 0.5 micro g/mL for all racemic compounds investigated. The effect of temperature, pH and concentration of the impregnating chiral selectors on resolution has been studied. 相似文献
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《Tetrahedron: Asymmetry》1999,10(17):3353-3364
Four new chiral selectors obtained by suitable derivatization of the hydroxyl groups of the deoxycholic acid with two identical (homoderivatized) or different (heteroderivatized) arylisocyanates have been prepared and linked covalently to silica gel to obtain new chiral stationary phases (CSPs) for the HPLC separation of enantiomers. The CSPs containing two identical substituents are able to enantiodiscriminate different classes of racemic compounds, or the same racemates to a different extent, a property which depends on the different electronic character of the arylcarbamate moieties. The heteroderivatized CSPs retain the character of the two homoderivatized phases: however, the relative position of the two different arylcarbamate moieties on the deoxycholic backbone strongly affects the enantiodiscrimination capability of these two CSPs. 相似文献
18.
Shabi Abbas Zaidi Seung Mi Lee Zeid A. AL Othman Abdullah M. AL Majid Won Jo Cheong 《Chromatographia》2011,73(5-6):517-525
Some acidic chiral templates were used to prepare open tubular (OT) molecule imprinted polymer (MIP) capillary columns to explore the effects of molecular structures of templates on chiral recognition capabilities and to verify the feasibility of the general MIP preparation protocol introduced in the previous study. The templates are phenyl carboxylic acids and their derivatives. Optimization was carried out for chiral separation of template enantiomers for each MIP column through varying pH and composition of eluent. It was found that the preparation protocol can be successfully applied for the appropriate templates with functional groups fulfilling the three-points interaction rule. The chiral separation performances were quite satisfactory for MIPs of such templates although they are yet inferior to the separation performances of the MIP columns fabricated with the templates of profen drugs (2-arylpropionic acids with a large substituent on the phenyl ring). Subtle variations of the template molecular structures have been found to be critical to enhance chiral recognition ability of the resultant MIP column. 相似文献
19.
Enantiomer separation of mandelates and their analogs, which are important intermediates in asymmetric synthetic and pharmaceutical chemistry, was investigated by capillary gas chromatography using different cyclodextrin derivative chiral stationary phases (CD CSPs). The used cyclodextrin derivatives included permethylated beta-CD (PMBCD), permethylated gamma-CD, heptakis(2,6-di-O-butyl-3-O-butyryl)-beta-CD, heptakis(2,6-di-O-pentyl-3-O-acetyl)-beta-CD and heptakis(2,6-di-O-nonyl-3-O-trifluoroacetyl)-beta-CD (DNTBCD), respectively. Among all the CSPs used, PMBCD and DNTBCD exhibited the broadest and best enantioselectivity for all the racemates investigated. Some thermodynamic parameters were evaluated and an enthalpy-entropy compensation effect was observed in enantiomer separation processes of mandelates and their analogs. Based on thermodynamic data and molecular mechanics calculations, the chiral recognition mechanism of mandelate derivatives on CD CSPs is discussed. 相似文献
20.
为了扩展多糖类手性固定相的种类,制备了基于淀粉及纤维素三(3-三氟甲基苯基氨基甲酸酯)的涂敷型手性固定相,以正己烷-异丙醇混合液为流动相,对8种手性化合物进行了高效液相色谱拆分。研究表明: 虽然与应用最广泛的分别以淀粉及纤维素三(3,5-二甲基苯基氨基甲酸酯)为手性选择因子的商品化手性柱Chiralpak AD和Chiralcel OD相比,所制备的手性固定相的手性分离能力较低,但纤维素三(3-三氟甲基苯基氨基甲酸酯)手性固定相显示出特异的手性识别能力,一些手性化合物在此固定相上得到了比在Chiracel OD上更好的分离;所制备的手性固定相的手性识别能力随流动相中异丙醇含量的降低而变好,当流动相中正己烷与异丙醇的体积比为95:5时所制备的手性固定相显示出相对较高的手性识别能力;总体来说,淀粉三(3-三氟甲基苯基氨基甲酸酯)手性固定相的手性识别能力稍强于纤维素三(3-三氟甲基苯基氨基甲酸酯)手性固定相,同时两种手性固定相的手性识别能力具有一定的互补性。 相似文献