扁桃酸及其类似物在全甲基环糊精固定相上的手性拆分

在全甲基β－环糊精（ＰＭＢＣＤ）和全甲基γ－环糊精（ＰＭＧＣＤ）手性固定相上,考察了扁桃酸酯、α－甲氧基扁桃酸酯、２－羟基－３－苯基丙酸酯和２－羟基－４－苯基丁酸乙酯的气相色谱手性分离行为。结果表明,所有研究的羟基羟基羧酸酯均可以在ＰＭＣＤ手性固定相上得到很好的手性分离,而ＰＭＧＣＤ对所研究的对映体没有任何手性拆分能力。结合和学参数,探讨了手性诉分机理。     

毛细管区带电泳法研究肾上腺素类药物的手性分离

使用β－环糊精（β－ＣＤ）及β－ＣＤ－羧甲基（ＣＭ－β－ＣＤ）作为手性选择剂,采用毛细管区带电泳法（ＣＺＥ）对去甲肾上腺素、肾上腺素和异丙肾上腺素的手性分离进行了研究。对影响这类药物手性分离的主要因素〔手性选择剂、背景电解质（ＢＧＥ）、分离体系的酸度和温度〕进行了讨论,并对手性识别机理进行了探讨。     

负电性和中性环糊精在毛细管电泳手性分离中的协同效应

１引言环糊精及其电中性衍生物（二甲基－β－环糊精（ＤＭ－β－ＣＤ）、三甲基－β－环糊精（ＴＭ－β－ＣＤ）、羟丙基－β－环糊精（ＨＰ－β－ＣＤ））是毛细管电泳（ＨＰＣＥ）手性分离中最常采用的手性选择剂,带电环糊精是ＨＰＣＥ手性分离中另一类重要的手性选择剂,它的带电性质使其在手性拆分过程中起到非常重要的作用。本文分别考察了带电的磺丁基－β－环糊精（ＳＢＢ－β－ＣＤ）与电中性的ＤＭ－β－ＣＤ、ＴＭ－β－ＣＤ以及ＨＰ－β－ＣＤ等３种双环糊精体系的手性拆分性能,研究了双环糊精在手性分离中所体现出的协同效应…     

γ－环糊精－SDS胶束电动色谱法分离十八甲基炔诺酮光学异构体

 研究了ＣＤ－ＳＤＳ胶束电动色谱（ＣＤ－ＭＥＫＣ）对电中性及疏水性的手性化合物的分离，并讨论了不同类型ＣＤ的手性识别作用。使用γ－ＣＤ可以有效地拆分十八甲基块诺酮（ＮＯＧ）旋光异构体。选择了最佳分离条件，通过调节ＣＤ和ＳＤＳ浓度以及其它操作条件可以把ＮＯＧ异构体很好的分离。     

γ－环糊精－SDS胶束电动色谱法分离十八甲基炔诺酮光学异构体

研究了ＣＤ－ＳＤＳ胶束电动色谱（ＣＤ－ＭＥＫＣ）对电中性及疏水性的手性化合物的分离，并讨论了不同类型ＣＤ的手性识别作用。使用γ－ＣＤ可以有效地拆分十八甲基块诺酮（ＮＯＧ）旋光异构体。选择了最佳分离条件，通过调节ＣＤ和ＳＤＳ浓度以及其它操作条件可以把ＮＯＧ异构体很好的分离。     

对萘普生和萘普生甲酯的毛细管电泳手性分离

以磺化β－ＣＤ作为手性分离添加剂,分别对萘普生和萘普生甲酯进行了手性分离研究,当磺化β－ＣＤ的浓度为３．５％（Ｗ／Ｖ）时,萘普生和萘普生甲酯的手性分离度都可大于２,但萘普生与萘普生甲酯不能达到同时拆分。如果同时以磺化β－ＣＤ和ＨＰ－β－ＣＤ作为作为手性分离添加剂,则可对萘普生甲酯达到同时拆分,当磺化β－ＣＤ和ＨＰ－β－ＣＤ的浓度分别为３．５％和１．５％（Ｗ／Ｖ）时,对萘磺生和萘普生甲酯两种消旋体的     

利用分子烙印手性固定相串联柱同时拆分两对对映体

采用复合功能单体制备了苯甲氧羰基－Ｌ－丝氨酸（Ｎ－Ｃｂｚ－Ｌ－Ｓｅｒ）和苯甲氧羰基－Ｌ－丙氨酸（Ｎ－Ｃｂｚ－Ｌ－Ａｌａ）烙印的分子烙印手性固定相。采用柱串联的方法,一次进样手性分离了苯甲氧羰基－ＤＬ－丝氨酸（Ｎ－Ｃｂｚ－ＤＬ－Ｓｅｒ）和苯甲氧羰基－ＤＬ－丙氨酸（Ｎ－Ｃｂｚ－ＤＬ－Ａｌａ）两对对映体,显示了分子烙印手性固定相在多对对映体同时手性分离的发展潜力。     

薄层色谱在有机物顺反及对映异构体分离中的应用

体异构体和光学异构体分离技术的发展已有较综合的论述ｌ‘”‘］。利用ＴＬＣ对光学异构体进行拆分的方法主要有两种。１）使用手性同定相ｌ’,‘］;２）利用手性流动相在非手性固定相上进行拆分ｒ‘。本文对立体异构体的分离采用一般的ＴＬＣ法,对对映异构体的分离选用ｐ－ＣＤ手性流动相,＊一奎宁手性流动相和手性固定相纤维素板及非手性Ｃ;ｓ反相板对三哇及氨基酸进行了拆分,并初步探讨了方形板及楔形板展开对分离效果的影响。１实验部分１．１试剂及材料二哩类化合物及标样均为自制,标样均通过元素分析;Ｄ,Ｌ一色氨酸,Ｄ一色…     

羧甲基—β—环糊精用于毛细管电泳中的手性分离

本文将水溶性良好的羧甲基－β－ＣＤ（ＣＭ－β－ＣＤ＿用于分离氯霉素中间体，考察了ＣＭ－β－ＣＤ作为毛细管电泳手性选择剂的分离性能。     

异噁唑啉及异噁唑烷类化合物在多糖衍生物类柱上的手性拆分

在ＣｈｉｒａｌｃｅｌＯＤ,ＣｈｉｒａｌｃｅｌＯＪ及ＣｈｉｒａｌｐａｋＡＤ等３种多糖类手性固定相上,以各种配比的正己烷－异丙醇为洗脱剂,对７种异口恶唑啉及异口恶唑烷类化合物的对映体进行了手性拆分。考察了这些外消旋物在这些手性柱上的色谱行为。实验结果表明,手性固定相上葡萄糖片段构型的差异和它们高级结构的不同以及手性固定相上的二甲基苯基氨基甲酸酯或对甲基苯甲酸酯等功能团与样品的极性基团之间的相互作用,可能是支配手性拆分的主要原因。方法已用于不对称１,３－偶极环加成反应产物的光学纯度鉴定。     

在多糖衍生物类色谱柱上手性拆分β-氨基醇及β-羟基 硫醚类化合物

在以正己烷-异丙醇为移动相的体系中,用ChiralcelOD,ChiralcelOJ及ChiralpakAD作为手性固定相对13种β-氨基醇及β-羟基硫醚类化合物对映体进行HPLC手性拆分,这些化合物至少能在一支柱上得到基线级分离。考察了它们于不同浓度配比的这类洗脱体系中在柱上的色谱行为。实验表明化合物取代基的性质明显影响它们在手性柱上的拆分。手性固定相与外消旋样品上的极性基团之间的氢键作用和π-π作用可能是进行手性识别的主要原因。方法已用于非手性环氧化合物不对称开环反应产物β-氨基醇及β-羟基硫醚类化合物的光学纯度鉴定。     

乙炔基氮杂环丙烷类化合物在Chiralcel OD柱上的高效液相手性拆分

用HPLC方法考察了11种乙炔基氮杂环丙烷类化合物在手性固定相Chiralcel OD柱上的色谱拆分行为。五种芳环上带有卤素，硝基和吡啶基的乙炔基氮杂环丙烷化合物的外消旋混合物在Chiralcel OD柱上能被很好地拆分。实验结果表明，手性固定相上的二甲基苯基氨基甲酸酯与外消旋样品上的极性基团之间的氢键作用，偶极-偶极作用和π-π作用可能是进行手性识别的主要原因。此方法已用于不对称氮杂环丙烷化反应产物光学纯度的鉴定。     

环氧酰胺类化合物在OD和AD柱上手性拆分的比较

在ChiralcelOD和ChiralpakAD等二支多糖类手性固定相上,以各种不同配比的正己烷-异丙醇为洗脱剂对十三种带有不同取代基的环氧酰胺类化合物的对映体进行了手性拆分。考察了这些外消旋体在这二支手性柱上的色谱行为。实验表明,环氧酰胺与手性固定相之间的手性作用(例如:偶极-偶极作用、氢键作用、π-π作用)和非手性作用(例如:空间效应)等的综合因素是支配手性拆分过程的主要原因。方法已用于环氧酰胺不对称反应产物的光学纯度鉴定。     

Application and comparison of derivatized cellulose and amylose chiral stationary phases for the separation of enantiomers of pharmaceutical compounds by high-performance liquid chromatography.

The direct high-performance liquid chromatographic separation of three pairs of structurally related enantiomers on derivatized cellulose and amylose chiral stationary phases (Chiralcel OD, Chiralpak AD and Chiralpak AS) was studied using hexane as the mobile phase with 2-propanol or ethanol as modifiers. The separation, retention and elution order of the enantiomers on the different columns using different alcohol modifiers were compared. The effect of structural variation of the solutes on their k' was noted. A reversal of elution order of one enantiomeric pair upon changing the mobile-phase modifier was observed. Chiralcel OD and Chiralpak AD columns provided different elution orders of the enantiomers, including a fourth pair of enantiomers that were not structurally related to the other three pairs.     

异噁唑啉及异噁唑烷类化合物在多糖衍生物类柱上的手性拆分

在ＣｈｉｒａｌｃｅｌＯＤ，ＣｈｉｒａｌｃｅｌＯＪ及ＣｈｉｒａｌｐａｋＡＤ等３种多糖类手性固定相上，以各种配比的正己烷－异丙醇为洗脱剂，对７种异口恶唑啉及异口恶唑烷类化合物的对映体进行了手性拆分。考察了这些外消旋物在这些手性柱上的色谱行为。实验结果表明，手性固定相上葡萄糖片段构型的差异和它们高级结构的不同以及手性固定相上的二甲基苯基氨基甲酸酯或对甲基苯甲酸酯等功能团与样品的极性基团之间的相互作用，可能是支配手性拆分的主要原因。方法已用于不对称１，３－偶极环加成反应产物的光学纯度鉴定。     

Comparative LC Enantioseparation of Novel PPAR Agonists on Cellulose- and Amylose-Based Chiral Stationary Phases

The LC enantiomeric separation of several dual PPARα/γ agonists on the commercially available Chiralcel OD and Chiralpak AD columns has been evaluated in normal phase mode using a mobile phase consisting in a mixture of n-hexane, 2-propanol and trifluoroacetic acid at constant volume ratio. Most compounds were separated as underivatized acids without requiring time consuming analysis. Some complementary selectivity was evidenced on the two investigated chiral stationary phases related to the different accessibility of the active sites of the helical cavities. Additional information on the chiral recognition mechanism were deduced from the chromatographic behaviour of some selected methyl esters.     

Separation of the enantiomers of 4-aryl-7,7-dimethyl- and 1,7,7-trimethyl-1,2,3,4,5,6,7,8-octahydroquinazoline-2,5-diones by chiral HPLC

Summary Analytical HPLC methods using derivatized cellulose chiral stationary phases have been developed for separation of the enantiomers of 25 racemic 4-aryl-7,7-dimethyl- or 1,77-trimethyl-1,2,3,4,5,6,7,8-octahydroquinazoline-2,5-diones, condensed derivatives of dihydropyrimidines. The enantiomers of the compounds were resolved by normal-phase chromatography on silica-based cellulose tris(3,5-dimethylphenylcarbamate) (Chiralcel OD) and amylose tris(3,5-dimethylphenylcarbamate) (Chiralpak AD) columns with mobile phases consisting of mixtures ofn-hexane and an alcohol (2-propanol, ethanol, or methanol) in different proportions. The mobile phase and the chiral stationary phase were varied to achieve the best resolution. The effect of the concentration of alcohol in the mobile phase was studied. The resolution obtained on the two columns was complementary.     

Stereoselective effects in the separation of enantiomers of omeprazole and other substituted benzimidazoles on different chiral stationary phases

The enantioselective separation of omeprazole on different chiral stationary phases was investigated. The two enantiomers could be resolved on three different phases with immobilized protein, Chiral-AGP, Ultron ES-OVM and BSA-DSC, employing aqueous mobile phases with 2-propanol as organic modifier. On Chiralpak AD, an amylose-based chiral stationary phase, the enantiomers of omeprazole and three analogues could be separated using a non-polar hexane-ethanol mobile phase. For omeprazole the retention order was reversed when 2-propanol was replaced with ethanol or methanol as the modifier of hexane in the mobile phase.     

Enantiomers of New Synthetic Pyrrolylphenylethanoneamine Mono-Amino Oxidase Inhibitor Compounds: Analytical and Semipreparative HPLC Separations, and Chiroptical Characteristics

The polysaccharide chiral stationary phases (CSPs) Chiralcel OD and Chiralpak AD, and the brush-type (R,R)-Whelk-01 chiral stationary phases have been evaluated to separate new synthetic pyrrolylphenylethanoneamine racemic compounds, potentially monoamine oxidase (MAO) inhibitors, under various mobile phase compositions, using various temperatures. The enantioseparation was evaluated by comparing the (R,R)-Whelk-01 column performance with those of Chiralpak AD and Chiralcel OD. Significant differences were observed in their chiral recognition, as revealed from their retention, selectivity, resolution and elution order. Performances of the Chiralpak AD column were superior to those of the Chiralcel OD and (R,R)-Whelk-01 columns. Some of the racemic compounds were resolved by semipreparative chromatography on Chiralpak AD column in order to study the chiroptical proprieties of the single enantiomers.     

Comparative Chiral Separation of Thalidomide Class of Drugs Using Polysaccharide-Type Stationary Phases with Emphasis on Elution Order and Hysteresis in Polar Organic Mode

The enantioseparation of four phthalimide derivatives (thalidomide, pomalidomide, lenalidomide and apremilast) was investigated on five different polysaccharide-type stationary phases (Chiralpak AD, Chiralpak AS, Lux Amylose-2, Chiralcel OD and Chiralcel OJ-H) using neat methanol (MeOH), ethanol (EtOH), 1-propanol (PROP), 2-propanol (IPA) and acetonitrile (ACN) as polar organic mobile phases and also in combination. Along with the separation capacity of the applied systems, our study also focuses on the elution sequences, the effect of mobile phase mixtures and the hysteresis of retention and selectivity. Although on several cases extremely high resolutions (R_s > 10) were observed for certain compounds, among the tested conditions only Chiralcel OJ-H column with MeOH was successful for baseline-separation of all investigated drugs. Chiral selector- and mobile-phase-dependent reversals of elution order were observed. Reversal of elution order and hysteresis of retention and enantioselectivity were further investigated using different eluent mixtures on Chiralpak AD, Chiralcel OD and Lux Amylose-2 column. In an IPA/MeOH mixture, enantiomer elution-order reversal was observed depending on the eluent composition. Furthermore, in eluent mixtures, enantioselectivity depends on the direction from which the composition of the eluent is approached, regardless of the eluent pair used on amylose-based columns. Using a mixture of polar alcohols not only the selectivities but the enantiomer elution order can also be fine-tuned on Chiralpak AD column, which opens up the possibility of a new type of chiral screening strategy.