衍生化高效液相色谱法拆分1,1′-联萘-2,2′-二酚光学异构体

以基碳酸酰氯作衍生化试剂 ,采用高效液相色谱拆分 1,1′ 联萘 2 ,2′ 二酚光学异构体。当采用LichrosorbSi 6 0 (4mm× 30 0mm ,5 μm)柱 ,紫外 2 75nm检测 ,正己烷 乙醇 (98.5 1.5 ,V V)为流动相 ,1,1′ 联萘 2 ,2′ 二酚单基碳酸酯的分离因子和分离度分别为 1.36 8、3.0 5 1;用正己烷 乙醚 (98.5 1.5 ,V V)为流动相 ,1,1′ 联萘 2 ,2′ 二酚双基碳酸酯的分离因子和分离度分别为 1.0 5 5、1.347。这一方法可简便、快速地测定联萘二酚单基碳酸酯拆分样品的光学纯度     

毛细管电泳法和高效液相色谱法拆分联萘二酚酸对映体

采用毛细管电泳法和高效液相色谱法直接拆分2,2′-二羟基-1,1′-联二萘-3,3′-二甲酸(HBNC)对映体.以四种不同的β-环糊精为手性添加剂,考察环糊精的种类与浓度、缓冲液pH值及浓度、分离电压、温度等因素对HBNC分离的影响.结果表明:采用10 mmol/L磺丁基醚-β-环糊精+20 mmol/L磷酸盐缓冲液(pH=7.0),20 kV分离电压,HBNC对映体在20 min内达到基线分离,分离度达到3.31.采用(S)-叔-亮氨酸基-(S)-1-(α-萘基)乙胺手性柱,正己烷-乙醇-三氟乙酸(97∶3∶0.2,V/V)流动相,HBNC对映体在40 min内也基本达到基线分离.     

衍生化高效液相色谱法拆分1,1'-联萘-2,2'-二酚光学异构体

以(艹孟)基碳酸酰氯作衍生化试剂,采用高效液相色谱拆分1,1:联萘-2,2'-二酚光学异构体.当采用Lichrosorb Si-60(4 mm×300 mm,5/μm)柱,紫外275 nm检测,正己烷/乙醇(98.5/1-5,V/V)为流动相,1,1'-联萘-2,2'-二酚单(艹孟)基碳酸酯的分离因子和分离度分别为1.368、3.051;用正己烷/乙醚(98.5/1.5,V/V)为流动相,1,1'-联萘-2,2'-二酚双(艹孟)基碳酸酯的分离因子和分离度分别为1.055、1.347.这一方法可简便、快速地测定联萘二酚单(艹孟)基碳酸酯拆分样品的光学纯度.     

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。     

以分子印迹聚合物为固定相手性拆分1,1′-联-2-萘酚及其衍生物

以(R)-(+)-1,1′-联-2-萘酚为模板分子,4-乙烯基吡啶为功能单体合成了分子印迹聚合物,将其作为高效液相色谱的固定相,研究其手性识别特性。对该固定相的手性拆分的色谱条件进行了优化。实验结果表明,合成的印迹聚合物对(R)-(+)-1,1′-联-2-萘酚具有较强的亲和力和特定的选择性,能有效拆分1,1′-联-2-萘酚对映体,分离因子最高达到12.25。通过优化色谱条件,该分子印迹聚合物还能对与1,1′-联-2-萘酚结构相似的衍生物5,6,7,8,5′,6′,7′,8′-八氢-1,1′-联-2-萘酚和1,1′-联萘-2-氨基-2′-酚进行手性拆分,分离因子分别达到1.51和2.40。     

醇存在下R,S-1,1′-2-联萘酚对映体的环糊精手性识别研究

以R,S-1,1′-2-联萘酚对映体为手性客体分子, 采用荧光探针法详细研究了各种醇对β-环糊精/(R或S)-1,1′-2-联萘酚对映体的手性包络和手性荧光猝灭等性质的影响, 结果表明, 醇的存在可显著影响R,S-1,1′-2-联萘酚对映体与β-环糊精形成包络物的包络形式和包络常数. 通过与该对映体的β-环糊精手性固定相高效液相色谱拆分法比较研究结果表明, 醇等第三客体分子可显著影响环糊精对对映体化合物的手性选择性和分离度.     

纤维素-三（4-甲基苯甲酸酯）手性固定相拆分5种芳基丙酸类药物对映体及其制剂的含量测定

采用纤维素-三（4-甲基苯甲酸酯）（CTMB）手性固定相,利用反相色谱法研究了氟比洛芬、普拉洛芬、布洛芬、萘普生、洛索洛芬5种芳基丙酸类手性药物的色谱拆分行为。考察了流动相组成、酸碱添加剂及柱温对上述5种药物对映体分离的影响,并通过热力学研究及对映体结构分析对CTMB固定相的手性拆分机理进行了探讨。结果表明,除萘普生采用乙腈-0.1%（v/v）甲酸溶液外,以甲醇-0.1%（v/v）甲酸水溶液为流动相可使普拉洛芬、洛索洛芬、氟比洛芬和布洛芬的对映体间的分离度均大于1.5,CTMB固定相对这5种芳基丙酸类药物的手性拆分能力依次为普拉洛芬>洛索洛芬>氟比洛芬>布洛芬>萘普生。在各自的优化色谱条件下,将方法应用于上述5种药物制剂的含量测定,结果令人满意。     

基于直链淀粉衍生物手性固定相的高效液相色谱-串联质谱法拆分4种β-受体阻滞剂对映体及其分离机制的探讨

建立了以直链淀粉衍生物为手性固定相的高效液相色谱-串联质谱(HPLC-MS/MS)直接拆分普萘洛尔、美托洛尔、阿罗洛尔和卡维地洛4种β-受体阻滞剂对映体的方法。考察了手性固定相的种类、流动相改性剂和添加剂的体积分数、柱温和流速等对4种药物对映体分离的影响。结果表明:在Chiralpak AD-H手性色谱柱上,在正己烷-乙醇-二乙胺(20∶80∶0.03,v/v/v)为流动相、流速0.550 mL/min、柱温40℃的条件下,普萘洛尔、美托洛尔、阿罗洛尔和卡维地洛对映体均达到基线分离,分离度分别为1.37、1.80、2.09和4.70。通过热力学研究及对映体结构分析对拆分机理进行了探讨,发现4种药物对映体的手性拆分均为焓驱动过程,而固定相的手性空腔对不同药物的拆分影响较大。研究结果为β-受体阻滞剂的深入研究提供了参考方法。     

冠醚手性固定相的合成及其性能评价

以R-联萘酚为原料,利用铃木反应改进合成了已有文献报道的R-(3,3'-二苯基-1,1'-二萘基)-20-冠-6,并将其涂敷于C18硅胶(平均粒径5μm,孔径120)上制成了可用于高效液相色谱手性拆分的R-(3,3'-二苯基-1,1'-二萘基)-20-冠-6冠醚固定相(CSP).在以p H=2的高氯酸溶液为流动相,流速为0.1 m L·min-1,柱温为25℃的条件下,研究了R-(3,3'-二苯基-1,1'-二萘基)-20-冠-6冠醚固定相(CSP)对13种α-氨基酸对映体的拆分能力,并将其拆分结果与商品CR(+)柱进行了对比.实验结果表明在此色谱条件下,有11种α-氨基酸对映体(苯甘氨酸、对羟基苯甘氨酸、蛋氨酸、酪氨酸、色氨酸、缬氨酸、亮氨酸、异亮氨酸、苯丙氨酸、谷氨酸、天冬氨酸)能得到不同程度的拆分,并且对其中6种α-氨基酸对映体的拆分效果要好于商品CR(+)柱.研究表明此冠醚手性固定相对α-氨基酸对映体有很好的手性识别能力,在对α-氨基酸对映体的拆分上能与商品CR(+)柱相媲美.     

联萘酚在涂敷型淀粉衍生物手性固定相上拆分中的吸热保留及对映体洗脱顺序反转

在正相条件下,探讨了手性化合物联萘酚、联萘酚二醋酸酯、联萘酚二磺酸酯、二溴代联萘酚、氢化安息香以及萘普生在涂敷型淀粉衍生物手性固定相Lux Amylose-2上的拆分,考察了流动相中极性醇添加剂的种类及含量、柱温等对手性拆分及对映体洗脱顺序的影响。氢化安息香获得理想的拆分,分离度可达17.76;联萘酚二醋酸酯、联萘酚二磺酸酯和二溴代联萘酚得到基线或部分分离,分离度分别为3.43、2.56和1.47;萘普生未得到拆分。联萘酚拆分中观察到溶剂诱导及温度诱导对映异构体洗脱顺序反转的现象,R-联萘酚表现出少见的吸热保留特征。结合这些现象对手性识别机理进行了探讨。     

几种除草剂农药在高效液相色谱手性固定相上的对映体分离

采用正己烷-极性醇正相体系为色谱流动相,稳杀得、萘丙胺等几种不同种类的除草剂农药在Pirkle刷型(S,S)-Whelk-O1手性柱或自制的纤维素三(3,5-二甲苯基氨基甲酸酯)(CDMPC)手性柱上获得了成功的手性分离。研究了流动相中醇类改性剂对手性识别的影响,初步探讨了手性识别的机理,并摸索出最佳的对映体分离条件。     

Preparation of Regioselectively Modified Amylose Derivatives and Their Applications in Chiral HPLC

Four regioselectively modified amylose derivatives with three different substituents at the 2-, 3-, and 6-positions were prepared and their enantioseparations in HPLC were examined. Investigations indicated that the nature as well as the arrangement of the substituents significantly influenced their enantioseparations and each derivative exhibited characteristic chiral recognition. Amylose 2-benzoyl-3-(3,5-dimethylphenylcarbamate or 3,5-dichlorophenylcarbamate)-6-((S)-1-phenylethylcarbamate) exhibited chiral resolving abilities comparable to the commercial available amylose tris(3,5-dimethylphenylcarbamate)-based column, Chiralpak AD and the racemic compounds shown in this study were most effectively resolved on these two derivatives. The influence of mobile phase on chiral resolution was also examined.     

Preparation of Regioselectively Modified Amylose Derivatives and Their Applications in Chiral HPLC

Four regioselectively modified amylose derivatives with three different substituents at the 2-, 3-, and 6-positions were prepared and their enantioseparations in HPLC were examined. Investigations indicated that the nature as well as the arrangement of the substituents significantly influenced their enantioseparations and each derivative exhibited characteristic chiral recognition. Amylose 2-benzoyl-3-(3,5-dimethylphenylcarbamate or 3,5-dichlorophenylcarbamate)-6-((S)-1-phenylethylcarbamate) exhibited chiral resolving abilities comparable to the commercial available amylose tris(3,5-dimethylphenylcarbamate)-based column, Chiralpak AD and the racemic compounds shown in this study were most effectively resolved on these two derivatives. The influence of mobile phase on chiral resolution was also examined.

     

Polysaccharide‐based chiral stationary phases as halogen bond acceptors: A novel strategy for detection of stereoselective σ‐hole bonds in solution

In the last few years, halogen bonds have been exploited in a variety of research areas both in the solid state and in solution. Nevertheless, several factors make formation and detection of halogen bonds in solution challenging. Moreover, to date, few chiral molecules containing electrophilic halogens as recognition sites have been reported. Recently, we described the first series of halogen‐bond‐driven enantioseparations performed on cellulose tris(3,5‐dimethylphenylcarbamate) by high‐performance liquid chromatography. Herein the performances of amylose tris(3,5‐dimethylphenylcarbamate) as halogen bond acceptor were also investigated and compared with respect to cellulose tris(3,5‐dimethylphenylcarbamate). With the aim to explore the effect of polysaccharide backbone on the enantioseparations, the thermodynamic parameters governing the halogen‐dependent enantioseparations on both cellulose and amylose polymers were determined by a study at variable temperature and compared. Molecular dynamics were performed to model the halogen bond in polysaccharide‐analyte complexes. Chiral halogenated 4,4′‐bipyridines were used as test compounds (halogen bond donors). On this basis, a practical method for detection of stereoselective halogen bonds in solution was developed, which is based on the unprecedented use of high‐performance liquid chromatography as technical tool with polysaccharide polymers as molecular probes (halogen bond acceptors). The analytical strategy showed higher sensitivity for the detection of weak halogen bonds.     

高效液相色谱法测定1,1’-联萘-2,2’-二酚的光学纯度

用高效液相色谱法测定了1,1’-联禁-2,2’-二酚的光学纯度。色谱柱:Si-5柱,流动相:石油醚／乙醇（93／7,V／V）。方法简便、快速、准确,准确度为98.6％～101.6％,相对平均偏差为1.01％。     

Polymer-supported BINOL ligand for the titanium-catalyzed diethylzinc addition to aldehydes: A remarkable positive influence of the support on the enantioselectivity of the catalyst

A new polymer-supported BINOL (1,1'-Bi-2-naphthol) was synthesized by coupling of aminomethyl polystyrene resin and (S)-2, 2'-dihydroxy-1,1'-binaphthyl-3,3'-dicarboxylic acid. This new ligand was found to be more enantioselective for the asymmetric addition of diethylzinc to aldehydes than its "free" analog [Ti(BINOL)(i)PrO(2)]. A range of 57-99% ee's as well as 78-97% yields was obtained, and the electronic properties of the enantioselectivity were also observed.     

Synthesis of mononuclear and dinuclear ruthenium(II) tris(heteroleptic) complexes via photosubstitution in bis(carbonyl) precursors

A novel, and quite general, approach for the preparation of tris(heteroleptic) ruthenium(II) complexes is reported. Using this method, which is based on photosubstitution of carbonyl ligands in precursors such as [Ru(bpy)(CO)(2)Cl(2)] and [Ru(bpy)(Me(2)bpy)(CO)(2)](PF(6))(2), mononuclear and dinuclear Ru(II) tris(heteroleptic) polypyridyl complexes containing the bridging ligands 3,5-bis(pyridin-2-yl)-1,2,4-triazole (Hbpt) and 3,5-bis(pyrazin-2-yl)-1,2,4-triazole (Hbpzt) have been prepared. The complexes obtained were purified by column chromatography and characterized by HPLC, mass spectrometry, 1H NMR, absorption and emission spectroscopy and by electrochemical methods. The X-ray structures of the compounds [Ru(bpy)(Me(2)bpy)(bpt)](PF(6))x0.5C(4)H(10)O [1x0.5C(4)H(10)O], [Ru(bpy)(Me(2)bpy)(bpzt)](PF(6))xH(2)O (2xH(2)O) and [Ru(bpy)(Me(2)bpy)(CH(3)CN)(2)](PF(6))(2)xC(4)H(10)O (6xC(4)H(10)O) are reported. The synthesis and characterisation of the dinuclear analogues of 1 and 2, [{Ru(bpy)(Me(2)bpy)}(2)bpt](PF(6))(3)x2H(2)O (3) and [{Ru(bpy)(Me(2)bpy)}(2)bpzt](PF(6))(3) (4), are also described.     

Embedding an allylmetal dimer in a chiral cavity: the unprecedented stereoselectivity of a twofold wittig [1,2]-rearrangement

After alpha,alpha'-dimetalation, both 2,2'-diallyloxy-1,1'-binaphthyl and 2,2'-di-2-methylallyloxy-1,1'-binaphthyl undergo the Wittig rearrangement with perfect diastereoselectivity. When racemic 1,1'-binaphthyl-2,2'-diol ("BINOL") is used as the starting material, it gives rise to a 1:1 mixture of antipodal stereoisomers, whereas enantiomerically pure (M)-2,2'-diallyloxy-1,1'-binaphthyl affords (M)-(S,S)-1,1-(1,1'-binaphthyl-2,2'-diyl)bis(2-propen-1-ol) as the sole product. The (M)-(S,S)/(P)-(R,R) mixture resulting from the rearrangement of racemic 2,2'-diallyloxy-1,1'-binaphthyl can be effectively subjected to a kinetic racemate resolution by applying the Sharpless-Katsuki asymmetric epoxidation. The single-sided Wittig rearrangement of 2-allyloxy-2'-propyloxy-1,1'-binaphthyl proceeds without any diastereoselectivity as this substrate can only be monometalated and hence is incapable of intramolecular aggregate formation which is instrumental for the observed stereoselectivity.     

Enantioseparations in nonaqueous capillary liquid chromatography and capillary electrochromatography using cellulose tris(3,5-dimethylphenylcarbamate) as chiral stationary phase

The potential of the widely used chiral stationary phase for high-performance liquid chromatography (HPLC) enantioseparations, cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC, sold under the trade name Chiralcel OD) was evaluated under the conditions of nonaqueous capillary electrochromatography (CEC). The effect of the particle size of the silica gel, the loading of CDMPC on the silica gel and nature of the organic solvent, as well as electrolyte salts on the separation characteristics were investigated. This study illustrates the applicability of CDMPC for obtaining highly efficient enantioseparations under the conditions of nonaqueous CEC. Comparative study of enantioseparations in capillary liquid chromatography (CLC) and CEC indicated the significant advantages of CEC such as higher plate number at the similar linear flow rates of the mobile phase as well as better tolerance of higher linear flow rates.     

Complexes of heteroscorpionate trispyrazolylborate ligands. Part VI. Carboxylate induced conversion of mono-ligand Tp′M(L) into bis-ligand Tp′2M complexes (M=Co(II) and Cu(II))

A series of homoleptic complexes of hexacoordinate cobalt(II) and copper(II) complexes with 3,5-disubstituted homo- and heteroscorpionate tris(pyrazolyl)borate anionic ligands (Tp′) were synthesized, i.e. bis[hydrotris(3-phenyl,5-methylpyrazol-1-yl)borato]cobalt(II), bis[hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3-methyl,5-phenylpyrazol-1-yl)borato]cobalt(II) and bis[hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3-methyl,5-phenylpyrazol-1-yl)borato]copper(II) and their structures were elucidated crystallographically. The complexes were also formed spontaneously during attempted metathesis of the corresponding Tp′M(NCS) complexes into Tp′M(OOCCH(OH)CH₃) complexes. In the case of the analogous conversion applied for the thiocyanato [hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3,5-dimethylpyrazol-1-yl)boratocobalt(II) complex with sodium carboxylates (lactate, pyruvate and 2-hydroxybutyrate), the cross-transfer of pyrazolyl residues between starting anionic ligands was observed resulting in formation of bis-ligand homo- and heteroleptic Tp′CoTp″ complexes, where Tp′, Tp″ were tris(pyrazolyl)borates composed of n 3(5)-phenyl,5(3)-methylpyrazolyl and (3−n) 3,5-dimethylpyrazolyl residues (n=0–3) identified by mass spectrometry. Metathesis of thiocyanate in thiocyanato hydrotris(3-phenyl,5-methylpyrazol-1-yl)boratocobalt(II) into pyruvate led to the isolation of stable the pyruvato hydrotris(3-phenyl,5-methylpyrazol-1-yl)boratocobalt(II) complex, the structure of which was determined crystallographically. The Tp′ ligands are η³ coordinated to metal ions in every case, whereas the pyruvate anion is coordinated through carboxylate and carbonyl oxygen atoms to the cobalt center. Two rotational isomers distinguishable by ¹H NMR spectroscopy for the hexacoordinate bis[hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3-methyl,5-phenylpyrazol-1-yl)borato]cobalt(II) complex were detected in solution.