手性溶剂-NMR法测定2,4-滴丙酸对映体纯度的定量分析

研究了手性溶剂法测定2,4-滴丙酸的^1H、^13C谱,在满足NMR准确定量所要求的分离度和信噪比的条件下,能准确测定手性化合物的对映体纯度。比较了以对映体百分含量（R％）和对映体过量（ee）表示手性农药的对映体纯度的差别,发现以对映体百分含量代替对映体过量来表示手性农药的对映体纯度更为准确。     

3种芳香连二醇对映体的毛细管区带电泳手性拆分及其光学纯度分析

以磺化环糊精为毛细管区带电泳(CZE)手性选择剂,成功地分离了3种烯烃的不对称二羟化产物苯基乙二醇、β-甲基苯基-乙二醇和1,2-二苯基乙二醇对映体;考察了不同手性选择剂及其浓度、背景电解质pH值、操作电压等因素对分离的影响,优化了分离条件;对该3种芳香连二醇对映体样品进行了光学纯度检查,并与HPLC测定结果作比较,评价该方法的准确性。结果表明:两批样品中对映体过量(ee)测定值与HPLC法结果相一致,CZE方法简单、准确、分离度好,可用于该芳香连二醇中性化合物的手性拆分和ee值的测定。     

高磺化-β-环糊精毛细管电泳分离分析手性芳香仲醇

以高磺化-β-环糊精为毛细管电泳手性选择剂,建立了有效分离7种手性芳香仲醇对映体的方法.在20 mmol/L H3PO4-三乙醇胺为背景电解质(pH 2.5),6%(m/V) 高磺化-β-环糊精为手性选择剂(S-β-CD),柱温20 ℃,操作电压-15 kV,检测波长214 nm等优化条件下,所有芳香仲醇对映体均实现基线分离.以本方法测定了7种芳香酮不对称氢转移反应产物7种手性芳香仲醇的百分对映体过量值(% ee),其测定结果与高效液相色谱、气相色谱测定结果完全一致.本方法可以用于手性芳香仲醇光学纯度的测定.     

气相色谱手性固定相进展

1966年Gil-Av等人首次用手性固定相在毛细管柱上分离了氨基酸对映体。至今这种方法已发展为研究和分离对映体的一种重要技术,并愈来愈多地用于天然产物绝对构象(外激素、香料成分等)的测定,不对称选择合成中对映体纯度及过剩量测定,手性药物中对映体纯度的测定,手性化合物在化学转移机理等方面的研究。目前气相色谱中用于分离对映体的     

核磁共振技术测定联萘酚的对映体纯度

手性联萘酚((±)-BINOL)制备是国内高校常开设的一个实验,其产品的对映体纯度测试是实验的重要一环。以2-甲酰基苯硼酸和(S)-(?)-1-苯乙胺的混合物作为手性试剂与联萘酚发生Bull-James Assembly反应,以此设计了核磁共振氢谱(¹H NMR)测定联萘酚对映体纯度的实验。实验结果表明,通过反应生成的对映体混合物的核磁信号,能准确地计算出(±)-BINOL的对映体纯度。以选定的苯环氢核信号计算出的(R)-BINOL含量与理论ee值有着良好的线性关系(R²=0.9999)。此实验方法能够快速完成大量学生样品的测量,同时大大减少实验废液的产生量。学生通过此实验可对核磁共振技术有更进一步的了解。     

模拟移动床色谱分离制备手性农药甲霜灵的研究

利用自行组建的模拟移动床色谱(SMBC),在正相条件下,在自制的涂敷型纤维素-三(3,5-二甲基苯基氨基甲酸酯)手性固定相上成功制备出甲霜灵对映体,所制备的对映体纯度达到99%以上,与高效液相色谱法制备相比较,模拟移动床技术制备甲霜灵对映体的效率以及流动相的利用率均明显高于高效液相色谱法.     

气相色谱法手性拆分氯代和溴代环氧苯乙烷

用手性毛细管气相色谱法 (使用 2 ,6 戊基 3 丙基 γ 环糊精柱 ,ChiraldexG PN)对 3种溴代环氧苯乙烷和 3种氯代环氧苯乙烷对映体进行了拆分 .初步讨论了对映体在该手性毛细管柱上的保留行为 .已用于此类化合物对映体过量值 (ee值 )的测定     

手性高效液相色谱法测定SR-生物丙烯菊酯对映体的光学纯度

 在自制的球形氨丙基硅胶上涂敷纤维素 三 (3,5 二甲基苯基氨基甲酸酯 ) (CDMPC) ,制备了手性固定相(CSP)。用该固定相优化了生物丙烯菊酯对映体的分离条件 ,利用色谱峰面积测定了 3种SR 生物丙烯菊酯对映体的光学纯度。结果表明 ,在CDMPC CSP上用高效液相色谱法 (HPLC)测定SR 生物丙烯菊酯对映体的光学纯度、评价样品的质量优劣是一种非常理想的方法。     

(R)-2-{[4-(3-甲氧基丙氧基)-3-甲基吡啶-2-基]甲基亚硫酰基}- 1H-苯并咪唑的合成

以2,3-二甲基吡啶为起始原料, 经过11步反应, 不对称合成了质子泵抑制剂的关键中间体: (R)-2-{[4-(3-甲氧基丙氧基)-3-甲基吡啶-2-基]甲基亚硫酰基}-1H-苯并咪唑. 研究了用手性高效液相色谱拆分对映体、测定产品光学纯度的方法, 结果表明目标产品的ee值达到99%. 通过IR, UV, MS以及1H NMR分析对重要中间体和目标产品进行了结构鉴定.     

色谱法测定手性四面体金属簇合物对映体过量值

在自制的直链淀粉-三(苯基氨基甲酸酯)(ATPC)高效液相色谱手性固定相(HPLC-CSP)上,优化了手性四面体金属簇合物的手性分离条件,测定了不同合成条件下得到的手性四面体金属簇合物C0M0(CO)5C5H4C(O)CH3(μη^2-HC≡CCH2OH)的对映体过剩值(ee)。结果表明,高效液相色谱手性固定相法是拆分这类化合物的一种理想方法。     

Quantitative 1H NMR method for the routine spectroscopic determination of enantiomeric purity of active pharmaceutical ingredients fenfluramine, sertraline, and paroxetine

Determining the enantiomeric purity of chiral therapeutic agents is important in the development of active pharmaceutical ingredients (API). A strategy for determining the enantiomeric purity of three APIs was developed using nuclear magnetic resonance (NMR) and the chiral solvating agent (CSA) 1,1-bi-2-naphthyl (1). While chiral chromatography is widely used to evaluate enantiomeric purity, it can sometimes suffer from tedious sample preparation obviating rapid measurements that are sometimes needed during the manufacture of such agents. The techniques described herein provide comparable enantiomeric purity results with those obtained with traditional chiral HPLC and other published methods for these compounds. Chiral analysis of standard samples of methylbenzylamine enantiomeric mixtures using 1 were found to be quantitative to approximately 1% minor enantiomer. Enantiomeric purity determination by NMR utilizing chiral solvating agents do not require special instrumental techniques, chemical derivatization or standards and is therefore ideally suited for rapid routine analysis. As a result, the technique demonstrated is commonly used in our laboratory as a complementary or alternative method to chiral HPLC or optical rotation measurements for routine determination of enantiomeric purity.     

Enantioseparation of four cis and trans diastereomers of 2',3'-didehydro-2',3'-dideoxythymidine analogs, by high-performance liquid chromatography and capillary electrophoresis

Compounds 1-4 are the four stereoisomers of a synthetic new potential antiviral agent (d4T analog) containing two chiral centers and a base (uracil). Both high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) techniques were used to separate and quantify enantiomers with high resolution. The determination of enantiomeric purity of the compounds was developed using both amylose chiral stationary phase by HPLC and anionic cyclodextrins (highly S-CD) as chiral selectors in CE. The HPLC method was found to be superior in sensitivity to the CE method.     

三七素手性拆分方法的研究

使用气相色谱法和高效液相色谱法分离了三七素对映体,并探讨了影响液相色谱法分离效果的因素。结果表明,HPLC法利用手性固定相进行直接拆分,无法实现对映体的完全分离;GC法和HPLC的手性试剂衍生化法均可对三七素对映体进行较好的分离。但GC法由于衍生化过程中副产物的存在,干扰了对映体的准确定量。手性试剂衍生化HPLC法,以邻苯二甲醛、N-酰化-L-半胱氨酸为衍生化试剂,反应得到的三七素对映体的衍生物在ODS柱上分离良好,且方法简单、快速。     

巴拉苏酰胺对映体的色谱分离研究

利用手性HPLC法对天然产物(+)-巴拉苏酰胺(balasubramide)及其对映体进行分离和光学纯度测定。在手性分离过程中,考察了两种不同的手性固定相和不同比例的流动相(正己烷和异丙醇),以进行手性分离方法的优化。结果表明:正己烷和异丙醇(70/30,V/V)在手性柱Chiralpak AD-H上获得最佳分离。光学活性的巴拉苏酰胺的对映体过量值高于98%,其分离因子(α)和分离度为2.15和21.80。本研究为光学活性的巴拉苏酰胺及其后续衍生物光学纯度控制提供了方法学基础。     

High-performance liquid chromatographic and capillary electrophoretic methods for the quantitation of the (S)-terbutaline in (R)-terbutaline

Summary The resolution of chiral drugs, metabolites and related substances continues to be an important area in pharmaceutical analysis. Two methods for the optical purity testing of (R)-(-)-terbutaline were developed, namely capillary electrophoresis using hydroxypropyl-β-cyclodextrin and high-performance liquid chromatography using a chiral stationary phase. Validation data such as linearity, recovery, detection limit, and precision of the two methods are presented. The detection limit of (S)-terbutaline in (R)-terbutaline was 0.05% by the HPLC method and 0.03% by the CE method. The was generally good agreement between the HPLC and CE results. These methods were found to be applicable as a practical quality control method for the enantiomeric purity determination of(R)-terbutaline.     

Chiral capillary electrophoretic determination of the enantiomeric purity of tetrahydronaphthalenic derivatives, melatoninergic ligands, using highly sulfated beta-cyclodextrins

Using cyclodextrin capillary zone electrophoresis (CD-CZE), baseline separation of synthetic tetrahydronaphthalenic derivatives, potential melatoninergic compounds, was achieved. A method for the enantioresolution of these tetralins and determination of their enantiomeric purity was developed using anionic CDs (highly sulfated-CD or highly S-CD) as chiral selectors and capillaries dynamically coated with polyethylene oxide (PEO). Operational parameters such as the nature and concentration of the chiral selectors, buffer pH, organic modifiers, temperature and applied voltage were investigated. The use of charged CDs provides a driving force for our neutral compounds in the running buffer and enantiomeric resolution by inclusion of compounds in the CD cavity. The highly S-beta-CD was found to be the most effective complexing agent, allowing good enantiomeric resolution. The complete resolution of three tetralin compounds was obtained using 25 mM phosphate buffer at pH 2.5 containing 2.5% w/v of highly S-beta-CD at 25 degrees C with an applied field of 0.25 kV/cm. The apparent association constants of the inclusion complexes were calculated. This optimized method was validated in terms of linearity, sensitivity, accuracy and recovery. The enantiomeric purity for the three molecules was determined and the detection limit of enantiomer impurities is about 0.3-0.6%.     

柱前衍生高效液相色谱法测定四氢噻唑-2-硫酮-4-羧酸的光学纯度

用苯胺对四氢噻唑-2-硫酮-4-羧酸(TTCA)进行柱前衍生,将其衍生物在手性固定相上拆分,通过二极管阵列紫外检测器和在线旋光检测仪对其衍生物进行检测,建立了一种拆分TTCA消旋体、测定TTCA光学纯度的新方法。以正己烷和乙醇或异丙醇为流动相,在DNB-Leucine手性固定相上对TTCA衍生物进行了拆分,并考察了流动相组成和柱温对其衍生物分离的影响,获得较优分析条件,分离因子大于1.2。非手性试剂苯胺柱前衍生化法测定(R)-TTCA的光学纯度与旋光度方法比较,结果一致,相对偏差小于1.34%。     

Determination of the enantiomeric purity of epinephrine by HPLC with circular dichroism detection

Several hundred drug substances approved by the U.S. Food and Drug Administration are chiral molecules. For the enantiomeric purity assessment, current practice is to develop separation techniques using chiral columns or mobile phase modifiers to separate enantiomers before detection. An alternative approach is to use currently accepted HPLC assay methods and use chiral-specific detectors to confirm whether the correct enantiomer is present. In this paper, adding a circular dichroism (CD) detector to an achiral HPLC method from the US Pharmacopeia (USP) is shown to be amenable for the determination of the enantiomeric purity of epinephrine, a substance used to treat anaphylaxis. This HPLC-UV-CD approach was able to detect the inactive D-(+) enantiomer at 1% of the total epinephrine composition. The linearity, accuracy, and precision of HPLC-UV-CD were evaluated and compared to analyses using a chiral HPLC method. Additionally, an epinephrine drug product was analyzed for assay (concentration) and enantiomeric purity. The results from achiral and chiral methods were identical within the experimental error. Overall, achiral chromatography performed using a USP method with CD detection may serve as a general means of determining chiral drug enantiomer purity and avoids the need for the development of additional chiral-specific methods for each individual drug.     

Catalytic, highly enantioselective Friedel-Crafts reactions of aromatic and heteroaromatic compounds to trifluoropyruvate. A simple approach for the formation of optically active aromatic and heteroaromatic hydroxy trifluoromethyl esters.

A new catalytic enantioselective synthetic method for the formation of optically active aromatic and heteroaromatic hydroxy-trifluoromethyl ethyl esters is presented. This catalytic enantioselective Friedel-Crafts reaction of trifluoromethyl pyruvate with aromatic and heteroaromatic compounds is catalyzed by a chiral bisoxazoline copper(II) complex and proceeds in good yield and with high enantiomeric excess. For a series of substituted indoles, the corresponding 3-substituted hydroxy-trifluoromethyl ethyl esters are formed in up to 93% yield and 94% ee. Pyrrole and 2-substituted pyrroles also react with trifluoromethyl pyruvate in a highly enantioselective aromatic electrophilic reaction and up to 93% ee and good yields are obtained. Furanes and thiophenes give the corresponding 2-hydroxy-trifluoromethyl ethyl esters in high enantiomeric excess; however, the yields of the products are only moderate. Various types of aromatic compounds react in this catalytic reaction with trifluoromethyl pyruvate to give the aromatic electrophilic addition product in good yield. To obtain high enantiomeric excess (> 80% ee) it is necessary that aromatic amines are protected with sterically demanding protecting groups such as benzyl or allyl. This prevents coordination of the amine nitrogen atom to the catalyst, as aromatic amines having a N,N-dimethyl group probably coordinate to the catalyst, leading to a significant reduction of the enantioselective properties of the catalyst. On the basis of the experimental results and the absolute configuration of the formed chiral center, the mechanism for the catalytic enantioselective Friedel-Crafts reaction is discussed.