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Separation methods for the resolution of “optical isomers” (especially enantiomers) are developed to solve either of two basic problems: 1) the need to obtain, in optically pure form, one antipode or the other on a scale suitable for further chemical use-i.e.-“preparative” or 2) the analysis of the extent of racemization or “optical resolution” of a mixture of enantiomorphs on a scale sufficient for quantitative analysis-i.e.-“analytical”. The most economical, large-scale separation methods in use today are not chromatographic in nature but rather range from such common, general unit operations as recrystal1ization to very specific biological degradation.lS2 Chromatographic methods are generally limited to systems in which analytical data is the desired end product or in which only relatively small amounts of resolved material are needed. 相似文献
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采用手性衍生化法,实验室合成了L-丝氨酸甲酯盐酸盐作为手性和衍生试剂,用于萘普生和-β-2-丙酸对映异构体的柱前衍生,以酰氯化间接衍生或缩水剂N,N‘-二环己基碳化二亚胺直接衍生形成酰胺非对映异构体对,然后用常规硅胶柱分离,同时利用色谱保留值规律和光谱特征吸收曲线综合进行定性分析。 相似文献
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The first resolution of enantiomers was performed 150 years ago–mechanically. Today a powerful method for carrying out this task is HPLC on polysaccharide derivatives as chiral stationary phases. Most racemates, from an analytical to a preparative scale, now appear to be resolved by this technique. As an example, the chromatogram for the enantiomeric resolution of a fullerene derivative is shown on the right. 相似文献
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Volker Schurig Hans-Peter Nowotny 《Angewandte Chemie (International ed. in English)》1990,29(9):939-957
In investigations concerned with the phenomenon of molecular chirality, the use of gas chromatography for the enantiomeric analysis of stable, volatile compounds is a technique of steadily growing importance. [1] In the last three years an important breakthrough in gas-chro-matographic separation of enantiomers has been achieved by using alkylated cyclodextrins (α, β, and γ) as chiral stationary phases in high-resolution capillary columns. In academic and commercial practice two different and complementary strategies have been adopted up to now. In the first, alkylated cyclodextrins are diluted with polysiloxanes and coated on glass or fused silica capillary columns. In the second, lipophilic per-n-pentylcyclodextrins and hydrophilic di-n-pentyl- and hydroxyalkylpermethylcyclodextrins are coated directly in the form of liquid phases onto suitably pretreated glass or fused silica surfaces. These techniques permit enantiomer separations not only for polar diols and alcohols, derivatized hydroxycarboxylic acids, amino acids, sugars, and alkyl halides, but also for nonpolar alkenes, cyclic saturated hydrocarbons, and metal π complexes. An important aspect for practical applications is that in many cases the enantiomers can be separated without previous derivatization. Whereas the resolution of racemates of unfunctionalized hydrocarbons is attributed to an enantioselective host–guest inclusion complex, some observations indicate that for polar guest molecules additional enantioselective interactions are also involved. The new chiral stationary phases can be used over a wide range of temperatures (25 to 250°C). The technique described is likely to become widely adopted as a simple, accurate and highly sensitive method for the enantiomeric analysis of chiral compounds that can be vaporized without decomposition. It will also stimulate future research aimed at finding universal cyclodextrin phases and elucidating the mechanisms of enantioselectivity. 相似文献
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2-苯基-1-环丙烷羧酸酯对映体的毛细管气相色谱分离研究 总被引:2,自引:0,他引:2
使用3-位酰基化的4种2,6-二-O-戊基-3-O-酰基化-β-环糊精衍生物和6-位酰基化的3种2,3-二-O-戊基-6-O-酰基化-β-环糊精衍生物作为毛细管气相色谱手性固定相,对4对2-苯基-1-环丙烷羧酸酯对映体(cis-2-PhCpOMe,cis-2-PhCpOEt,trans-2-PhCpOMe,trans-2-PhCpOEt)进行分离研究。结果表明,对所拆分的4对2-苯基-1-环丙烷羧酸酯对映体而言,3-位酰基化的4种2,6-二-O-戊基-3-O-酰基化-β-环糊精衍生物比6-位酰基化的3种2 相似文献
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Separation of enantiomers is a very urgent problem in biochemical medicine and unsymmetry synthesize. High performance liquid chromatography is a powerful means in separation of enantiomers. In this study chiral stationary phase method of high performance liquid chromatography was used to separate Naproxen enantiomers, the derivative of (RS)-2-(6-methoxyl-2-naphthyl) propionic acid (namely mixed acid sample). Photodiode array detector was used to do qualitative analysis. 相似文献
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以β-环糊精作为手性流动相添加剂,研究了佐匹克隆对映体在反相高效液相色谱系统中的拆分情况。探讨了β-环糊精浓度、流动相中甲醇含量、流动相pH值、流动相流速及温度等因素对佐匹克隆对映体拆分的影响。通过采用单一变量法对实验条件进行考察,最终得到了佐匹克隆对映体手性拆分的最佳色谱条件。结果表明:当采用Inertsil ODS-SP(5μm,4.6 mm×250 mm)色谱柱,甲醇为有机相,流动相为20mmol/L磷酸二氢钾缓冲液(含15 mmol/Lβ-环糊精)-甲醇(85∶15),流速为0.8 mL/min,pH值为5.5,温度为35℃,紫外检测波长为305 nm,进样量为20μL时,佐匹克隆对映体得到良好分离,其对映体的保留时间分别为67.42 min和74.48 min,分离度(R)为1.62。该方法操作简单,灵敏度高,拆分效果理想,且比手性固定相法成本低,从而为佐匹克隆对映体的进一步深入研究提供了一种新方法。 相似文献
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采用高效液相色谱法,以手性冠醚Crownpak CR( )为固定相、高氯酸溶液/甲醇混合溶液为流动相,成功地实现了色氨酸(Trp)对映体的色谱分离.考察了流动相中甲醇含量、流量和柱温等因素对分离效果的影响.研究表明,适当提高流动相中的甲醇含量、降低流动相流量、降低柱温可以有效地提高分离度.另一方面,提高流动相中的甲醇含量、提高流动相流量、升高柱温可以显著地缩短样品的保留时间.确定了一种最佳分析分离条件,即流动相为甲醇∶高氯酸溶液=15∶85(V/V),流动相流量0.8 mL/min,柱温20℃,波长220 nm,在此条件下进行色谱分离,样品的保留时间小于12 min,分离度达到2.06.该方法具有快速、高效、准确和精密度高等优点. 相似文献
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The aim of this study was to observe the chiral separation of a series of C2-asymmetric bi-naphthyl compounds on molecularly imprinted polymers (MIPs) using 1,1′-bi-2-naphthol (BINOL) as template. MIP prepared using 4-vinylpyridine as the functional monomer showed better chiral recognition for the template than the MIPs prepared using acrylamide, 2-(diethylamino)ethylmethacrylate and 2-vinylpyridine, respectively. 1H-NMR was used for comparison of the interactions between template and functional monomers. For chromatographic analysis the effects of mobile phase and temperature on the chiral separation were investigated. When 4-vinylpyridine was employed as the functional monomer, chiral separation of 1,1′-bi-2-naphthol and its analogues were studied. The MIP also demonstrated an ability to discriminate between enantiomers of structurally related compounds that had not been imprinted. The thermodynamic parameters of interactions between substrates and MIP in acetonitrile based mobile phase were investigated by the Van’t Hoff equation. In this study, the specific hydrogen-bonding interactions seemed to be the key factor to achieve chiral separation. 相似文献
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Bupivacaine is an amide type local anesthetic widely used in surgery and obstetrics because of its sustained peripheral and central nerve blockade. R-(+)-bupivacaine is more toxic to the central nervous and the cardiovascular systems than S-(?)-bupivacaine. To obtain S-(?)-bupivacaine with high degree of purity using a continuous simulated moving bed (SMB) unity, equilibrium and mass transfer parameters under dilute conditions were obtained by pulse experiments using 0,0′-bis[4-terc-butyl-benzoyl]-N,N′-diallyl-L-tartar diamide immobilized in silica (Kromasil® CHI-TBB). The linear equilibrium constants were found to be 2.12 and 2.91 for R-(+)-and S-(?)-bupivacaine, respectively. Axial dispersion coefficients were found to be practically the same for both enantiomers. A fast kinetic of mass transfer was observed. The internal resistance to the mass transfer controls all the mass transfer process in this chiral column and the pore diffusion coefficients were of the order 10?7cm2/s. The equilibrium and mass transfer parameters will be employed in future simulation and design of operating conditions of SMB unity. 相似文献
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Volker Schurig 《Angewandte Chemie (International ed. in English)》1984,23(10):747-765
If a stationary phase A employed in gas chromatography possesses a chemical affinity for substance B, which is to be separated, then the retention behavior is not only determined by the normal physical equilibrium between the gas and liquid phases but also by the chemical equilibrium A + B ? AB. If A and B are chiral and A is present in optically active form while B is a racemic mixture, then it is possible to achieve a gas chromatographic enantiomer resolution without the isolation of diastereomers: the energetically different diastereomeric associates AR BR and AR BS are formed rapidly and reversibly. This enantiospecific resolution principle was first demonstrated in 1966 by the quantitative resolution of racemic amino acid derivatives on optically active peptide phases in analogy to the well-known stereospecificity of enzymes. The anchoring of the chiral resolving agent to thermally stable polysiloxanes together with the employment of high resolution capillary columns and the use of appropriate derivatization strategies has led to the development of enantiomer resolution into a routine modern method for many classes of substances. The demonstration of enantiospecificity in the gas chromatographic separation process is of fundamental interest, and its systematic study can result in a significant contribution to the understanding of the molecular mechanism of “chiral recognition”. The gas chromatographic separation of enantiomers has also proven to be an accurate and sensitive method for the determination of the enantiomeric composition of natural products and products of enantioselective transformations (asymmetric syntheses, “chiral pool” transformations, kinetic resolutions, biomimetic reactions) and for the quantification of racemization, e.g. in the synthesis and hydrolysis of peptides. In any research program devoted to the phenomenon of chirality, the gas chromatographic separation of the enantiomers of volatile compounds constitutes an indispensable modern instrumental technique. 相似文献
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混合萃取剂拆分氧氟沙星外消旋体 总被引:1,自引:0,他引:1
将混合萃取剂技术应用于氧氟沙星外消旋体的萃取分离,主要研究了氧氟沙星对映体在水和有机溶剂两相中的萃取分配行为。研究结果表明:在L-(-)-对甲基二苯甲酰酒石酸(L-DTTA)的浓度为0.18mol/L,L-(-)-二苯甲酰酒石酸(L-DBTA)的浓度为0.12mol/L,氧氟沙星浓度为0.2mg/mL,萃取温度为25℃,pH为7.00时,L型对映体和D型对映体的分配系数分别达到10.2和4.20,手性选择性达到2.43。 相似文献