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。     

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。     

Preparation of chiral stationary phase via activated carbamate intermediate for liquid chromatographic optical resolution

Summary Chiral stationary phases (CSPs) for liquid chromatography were prepared by the way of an activated carbamate intermediate. The amino group of aminopropylsilyl silica gel was first activated by carbamylation with disuccinimido carbonate (DSC). The obtained activated carbamate silica gel (ACsil) proved useful as an intermediate for the preparation of urea-type CSPs. The reaction of ACsil with (S)- of (R)-1-(α-naphthyl)-ethylamine gave naphthylethylurea type CSPs. These CSPs were also obtained directly from aminopropylsilyl silica gel by its reaction with optically active (S)- or (R)-succinimido 1-(α-naphthyl)ethyl carbamate (SINEC). Several phenylthiohydantoin amino acid enantiomers and p-bromophenylcarbamyl amino acid enantiomers were resolved on the CSPs by elution with aqueous mobile phase.     

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。     

Enantiomeric resolution of anti-HIV agents on a cellulose derivative chiral stationary phase

Summary Anti-HIV enantiomeric 1H, 3H-thiazolo[3, 4-a] benzimidazoles have been stereospecifically analyzed by elution on a column of cellulose tris-(4-methyl-phenylbenzoate)ester adsorbed on macroporous silica (Chiralcel^R OJ).The enantiomeric resolution of the compounds examined is linked to a complex and competitive contribution of different factors.     

Enantiomeric resolution of anti-HIV agents on a cellulose derivative chiral stationary phase. Note II

Summary A series of enantiomeric 1H,3H-thiazolo[3,4-a] benzimidazoles with anti-HIV activity has been stereospecifically analyzed.The enantiomeric resolution has been carried out by means of an HPLC method using a column of cellulose tris-(4-methyl-phenylbenzoate) ester adsorbed on macroporous silica gel (Chiralcel^R OJ).     

Enantiomeric and diastereomeric high-performance liquid chromatographic separation of cyclic beta-substituted alpha-amino acids on a teicoplanin chiral stationary phase

High-performance liquid chromatographic (HPLC) separation of stereomeric cyclic beta-substituted or-quaternary alpha-amino acids was performed on a chiral stationary phase based on the glycopeptide antibiotic teicoplanin. The investigated amino acids are the 1-amino-2-methylcyclohexanecarboxylic acids, the 1-amino-2-hydroxycyclohexanecarboxylic acids, Ala, Cha, Phe and Tle. The effects of the mobile phase composition (type and content of organic modifier, pH) and of the temperature on the enantio- and diastereoselectivity were studied and the conditions were optimised to resolve the four stereomers of one amino acid in a single chromatographic run. The influence of the modifier concentration and the pH of the mobile phase reveal two enantiomeric and diastereomeric discrimination mechanisms based on different interactions with the stationary phase. For optimal separation of diastereomers the column has to be conditioned with an acidic eluent.     

Direct chromatographic resolution of carnitine and O-acylcarnitine enantiomers on a teicoplanin-bonded chiral stationary phase.

R-(-)-Carnitine (vitamin B(T)) plays an important role in human energy metabolism, by facilitating the transport of long-chained fatty acids across the mitochondrial membranes. Its (S)-enantiomer acts as a competitive inhibitor of carnitine acetyltransferase, causing depletion of the body R-(-)-carnitine stock. Consequently, the separation of carnitine enantiomers is very important both to study their biological activities and to control the enantiomeric purity of pharmaceutical formulations. In the present paper we describe an easy, fast and convenient procedure for the separation of the enantiomers of carnitine and O-acylcarnitines by enantioselective HPLC on a laboratory-made chiral column containing covalently bonded teicoplanin as selector. High enantioselectivity factors (alpha values ranging from 1.31 to 3.02) and short-time analyses characterize the analytical procedure; in addition, analytes are easily detected by evaporative light scattering with no need for preliminary derivatization. The effects of pH and ionic strength of the mobile phase and of the nature of the organic modifier on the enantioselective separations were also investigated.     

Enantiomeric separation of chiral pesticides by high performance liquid chromatography on cellulose tris-3,5-dimethyl carbamate stationary phase under reversed phase conditions

Twenty chiral pesticides were tested, of which seven samples were directly separated by HPLC using cellulose tris-3,5-dimethyl carbamate (CDMPC) chiral stationary phase under RP conditions. The influence of mobile phase composition and column temperatures from 0 degrees C to 40 degrees C on the separations were investigated. The mobile phases were methanol/water or ACN/water at a flow rate of 0.8 mL/min with UV detection at 230 or 210 nm. Epoxiconazole, terallethrin, benalaxyl, and diclofopmethyl were observed to obtain the baseline separation under suitable conditions and other pesticides pyriproxyfen, lactofen, and quizalofop-ethyl were separated partially. The retention factors (k) and selectivity factor (alpha) for the enantiomers of most investigated pesticides decreased upon increasing the temperature except for the selectivity factors (alpha) of pyriproxyfen in methanol/water. The ln alpha - 1/T plots for racemic chiral pesticides were linear at the range of 0-40 except for that of pyriproxyfen enantiomers in methanol/water and the chiral separations were controlled by enthalpy. Better separations were not always at low temperature. The elution orders of the eluting enantiomers were determined by a circular dichroism (CD) detector.     

New chiral crown ether stationary phase for the liquid chromatographic resolution of alpha-amino acid enantiomers

A new chiral stationary phase (CSP) for the liquid chromatographic separation of enantiomers was prepared by bonding a novel enantiopure (diphenyl-substituted 1,1'-binaphthyl) crown ether to 5 microm silica gel. The resulting CSP was applied to the separation of the enantiomers of various natural and unnatural alpha-amino acids. All alpha-amino acids tested were resolved very well on the new CSP, with the exception of proline, which does not contain a primary amino group. The resolution of alpha-amino acid enantiomers on this new CSP was found to be dependent on the type and amounts of organic and acidic modifiers, and on column temperature.     

Enantiomeric resolution of new aromatase inhibitors by liquid chromatography on cellulose chiral stationary phases

Analytical HPLC methods using derivatized cellulose chiral stationary phases were developed for the direct enantioseparation of substituted [1-(imidazo-1-yl)-1-phenylmethyl)]-benzothiazolinone and benzoxazolinone derivatives with one chiral center. Those analogues of fadrozole constitute new potent nonsteroidal inhibitors of aromatase (P450 arom). The separations were made using normal phase methodology with a mobile phase consisting of n-hexane-alcohol (ethanol, 1-propanol, or 2-propanol) in various proportions, and a silica-based cellulose tris-3,5-dimethylphenylcarbamate (Chiralcel OD-H), or tris-methylbenzoate (Chiralcel OJ). The effects of concentration of various aliphatic alcohols in the mobile phase were studied. A better separation was achieved on cellulose carbamate phase compared with the cellulose ester phase. The effects of structural features of the solutes along with the temperature of the column on the discrimination between the enantiomers were examined. Baseline separation (Rs > 1.5) was easily obtained in many cases.     

用高效液相色谱手性固定相法拆分芳香仲醇及芳香乙二 醇类手性化合物

在ChiralcelOD和ChiralcelOJ两支多糖类手性固定相上，以各种不同配比的正己烷-异丙醇为洗脱剂对38种带有不同取代基的芳香仲醇及芳香乙二醇类手性化合物的对映体进行拆分，考察了这些外消旋体在这两支手性柱上的色谱行为。结果表明，扬长避短一柱对这些化合物的拆分能力与化合物取代基的性质和位置有关，这些化合物与手性固定相之间的氢键作用和π-π作用是影响手性拆分的重要原因。拆分方法已应用于潜手性酮不对称还原产物的光学纯度的鉴定，并取得了很好的效果。     

丁香酚键合硅胶液相色谱固定相的制备和色谱性能

采用固液相表面连续反应法,先将偶联剂γ-[(2,3)-环氧丙氧]丙基三甲氧基硅烷(KH-560)键合到球形硅胶表面,然后再将植物有效成分丁香酚与硅胶上的KH-560活性基团反应,合成了丁香酚键合硅胶液相色谱固定相(EGSP)。采用元素分析、热重分析和红外光谱对该固定相的结构进行了表征。以萘作为溶质探针,乙腈-水(35:65, v/v)为流动相,流速为0.8 mL/min,测得EGSP柱的柱效。以一系列的中性、碱性和酸性化合物为溶质探针,C₁₈柱和苯基柱作参比,对该固定相的色谱性能及保留机理进行了研究。结果表明,硅胶表面成功键合上了丁香酚配体,键合量为0.28 mmol/g, EGSP柱理论塔板数约为24707 N/m。该固定相不仅具有良好的反相色谱性能,同时由于配体结构中含有芳环、烯基和甲氧基,还能与溶质发生π-π电荷转移、偶极-偶极和氢键作用。与传统的反相C₁₈柱和苯基柱相比,EGSP在极性芳香族化合物的快速、简便分离中占优势。     

Enantiomeric resolution of underivatized small peptides by HPLC with a chiral crown ether stationary phase

Factors influencing the stereoisomeric resolution of underivatized dipeptides and a representative tripeptide on Crownpak (CR) columns have been investigated. The elution order and relative retention suggest that a combination of chiral, steric, and hydrophobic interactions effects the extent of chiral recognition and the retention achieved during separations. Some dipeptides whose amine terminus is located three atoms from the asymmetric center (such as dipeptides of D ,L -glycine) were resolved, but the elution order was the opposite of that expected for the type of Crownpak column used (CR(+)). Peptides containing hydrophobic substituents were strongly retained, but their retention times could be significantly reduced, and detectability improved, by use of gradient elution. Analysis of a commercial sample of D ,L -leucine-D ,L -alanine revealed the stereoisomers to be present in an unexpected quantitative ratio and demonstrated the utility of these separations for quality assurance and quantitative analyses.     

直链淀粉手性固定相拆分联二萘酚对映体

建立了联二萘酚对映体的高效液相色谱拆分方法。使用ChiralpakAD-H手性色谱柱,考察了流动相中极性调节剂的种类和比例、柱温以及流速对拆分联二萘酚对映体的影响。确定了最佳拆分条件:流动相为V(正己烷):V(乙醇)=55:45;流速为0.8mL/min;检测波长254nm;柱温30℃。计算了联二萘酚与固定相相互作用的焓变差值Δ(ΔH0)和熵变差值Δ(ΔS0)分别为-2.10kJ/mol和-4.94J/(mol.K),并考察了在以乙醇或异丙醇为极性调节剂流动相中两对映体的出峰顺序,结果发现在这两种流动相中出峰顺序是相反的。方法可用于联二萘酚的手性分离与检测。     

直链淀粉手性固定相法分离利阿唑对映体

建立了利阿唑对映体的高效液相色谱拆分方法。采用Chiralpak AD-H手性柱在正相条件下直接拆分利阿唑对映体,考察了流动相中有机极性调节剂的种类和浓度、酸碱的种类和含量、柱温及流速等对利阿唑对映体分离的影响。确定了最佳的拆分条件:流动相为正己烷-乙醇(含0.3%二乙胺和0.1%冰醋酸)(体积比为80∶20),流速0.6 mL/min;检测波长254 nm;柱温20 ℃。在此条件下利阿唑对映体的分离度为3.4。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。