万古霉素及其苯异氰酸酯衍生物手性固定相的制备与应用

采用"一锅法",以1,6-二异氰酸正己酯作间隔臂,制备了万古霉素及苯异氰酸酯衍生化的万古霉素手性固定相。对拉米夫定、拉米夫定的L-薄荷醇酯、酞胺哌啶酮和盐酸氟西汀进行了手性分离研究,在极性有机相模式下,研究了流动相甲醇中冰醋酸-三乙胺浓度和比例对手性分离的影响,观察到两种手性固定相具有不同的手性识别能力。在万古霉素手性固定相上4种溶质都获得了基线分离;在苯异氰酸酯衍生化的手性固定相上除盐酸氟西汀外也均获得基线分离。     

Chromatographic Enantioseparation of Ten Amino Acid Amide Derivatives on Three Polysaccharide-Based Chiral Stationary Phases

Enantioseparation of ten kinds of amino acid amide derivatives bearing aniline moieties on three polysaccharide-based chiral stationary phases (CSPs) was first systematically investigated. The chromatographic experiments were performed in the normal phase mode, namely, with n-hexane and 2-propanol as mobile phase. The effects of chiral columns, concentration of 2-propanol and column temperature on the enantioseparation were studied in detail. These compounds can be well resolved on Chiralcel OD-H column with the resolution above 1.5. Enantioseparation mechanism of chiral analytes and the CSPs are proposed based on the thermodynamic analysis of the experimental data. Our study establishes a simple, fast and efficient analytical method for amino acid amide derivatives by chiral HPLC, and provides a reference for enantioseparation of chiral amino acid amide derivatives and similar chiral compounds.     

The study of enantioseparation of zolmitriptan on vancomycin-bonded chiral stationary phase

In this study, the chiral stationary phase was prepared by bonding vancomycin to 5 microm spherical silica gel according to "one-pot" synthetic strategies, and used to separate the enantiomers of zolmitriptan under polar ionic mode. The influences of mobile phase composition, such as the concentration and ratio of glacial acetic acid (HOAc) and triethylamine (TEA), on the enantioseparation were investigated, and the chiral recognition mechanism is discussed. It was found experimentally that the retention factors were increased with the increase of the HOAc/TEA concentration in a certain extent, and the ionic interactions, hydrogen bondings, and steric interactions may play key role together. The method is suitable for baseline separation of zolmitriptan enantiomers.     

Enantioseparation of selected chiral sulfoxides using polysaccharide-type chiral stationary phases and polar organic, polar aqueous-organic and normal-phase eluents

HPLC enantioseparation of selected chiral sulfoxides was studied using cellulose and amylose phenylcarbamate derivatives as chiral stationary phases (CSPs). The contributions of various functional groups of a chiral analyte as well as the polysaccharide derivatives in the analyte retention and chiral recognition were evaluated. A very high enantioseparation factor exceeding 110 was observed in the enantioseparation of 2-(benzylsulfinyl)benzamide (BSBA) on cellulose tris(3,5-dichlorophenylcarbamate) (CDCPC) CSP by using 2-propanol as a mobile phase. The enantiomer elution order was opposite on cellulose and amylose phenylcarbamates. For the polysaccharide-type CSPs, pure alcohols such as methanol, ethanol and 2-propanol represent a valuable alternative to more common alcohol-hydrocarbon and reversed-phase eluents.     

大环糖肽抗生素键合相高效液相色谱法拆分7种氨基带保护基的氨基酸对映体

采用高效液相色谱法在装有大环糖肽抗生素键合相的手性柱上拆分了7种氨基带有芴甲氧羰基(fluorenylmethoxycarbonyl,Fmoc)保护的氨基酸对映体。比较了Fmoc-缬氨酸和相应的不带保护基的缬氨酸对映体在不同流动相体系中的色谱保留行为;考察了甲醇-醋酸-三乙胺流动相体系中醋酸和三乙胺的浓度以及它们二者的浓度之比对N-Fmoc氨基酸对映体拆分效果的影响。实验结果表明分离温度及流动相流速的变化也会对分离结果产生影响。该法简便快速,已成功地用于这类氨基酸的光学纯度测定。     

单硫代和双硫代甘油醚在直链淀粉-三（3,5-二甲基苯基氨基甲酸酯）固定相上的手性拆分

 合成了直链淀粉-三(3,5-二甲基苯基氨基甲酸酯）手性固定相。用该固定相对6种单硫 代 甘油醚和4 种双硫代甘油醚进行了手性拆分。单硫代甘油醚对映异构体得到了较好的分离, 而双硫代甘油醚完全不能拆分。提出了样品与固定相的作用模式。     

Improvement of proline chiral stationary phases by varying peptide length and linker

Seven new stationary phases with different number of proline units and/or different linkage to silica gel were prepared and evaluated in order to improve the performance of proline chiral stationary phases. The average separation factor achieved with the 53 analytes increases with the number of proline units in the stationary phases. When the proline peptides are directly attached to the 3-methylaminopropyl silica gel without using the 6-methylaminohexanoic acid linker, the stationary phases perform better overall. For decaproline chiral stationary phase 8, the separation also depends on the mobile phase system used. For this stationary phase, the CH2Cl2/hexanes/2-propanol system significantly outperforms the 2-propanol/hexanes system. For the 53 analytes tested, the separation factors achieved with this stationary phase compare well with those for three commercial columns.     

2-芳基丙酸类手性药物色谱拆分的热力学研究

以0.5%和1.0%(体积分数)正丙醇-50 mmol/L磷酸盐缓冲液(pH 6.41)为流动相,温度74~313 K,在Chiral-AGP柱手性固定相上,考察了萘普生和布洛芬对映体在手性柱上的保留和分离行为。在实验范围内,温度升高对分离不利,随着温度的升高,对映体的保留时间、分离度和选择性因子都减少;萘普生对映体的分离度均比布洛芬大;流动相含1.0％正丙醇时,萘普生对映体和布洛芬对映体达到完全分离应控制的最高温度分别为298和288 K。用ln k对1/T作图得到的Van’t Hoff曲线都具有良好的     

Enantioseparation of 2-aryloxypropionic acids on chiral porous monolithic columns by capillary electrochromatography. Evaluation of column performance and enantioselectivity

The enantioseparation of 2-aryloxypropionic acids by capillary electrochromatography was tested on columns with a monolithic stationary phase prepared from silanized fused-silica capillaries (100 microm I.D.) by in situ copolymerization of glycidyl methacrylate, ethylene glycol dimethacrylate and methyl methacrylate in the presence of formamide and 1-propanol as the porogen solvents. The porous chiral monolithic stationary phases were prepared by reaction of the epoxy-groups at the surface of the monolith with (+)-1-(4-aminobutyl)-(5R,8S,10R)-terguride. To attain the minimum HETP values for the enantiodiscrimination of 2-phenoxypropionic acid, the influence of the composition of polymerization solution on column total porosity and efficiency was investigated. Optimum mobile phase conditions were found for all analytes tested using acetonitrile-methanol mixtures containing triethylamine and acetic acid as the buffer components. Furthermore, the chemical and mechanical stabilities of the columns were satisfactory, allowing hundreds of analyses.     

Enantioseparation characteristics of the chiral stationary phases based on natural and regenerated chitins

Natural and regenerated chitins were derivatized with 3,5‐dimethyphenyl isocyanate. The corresponding chiral stationary phases were prepared by coating the resulting chitin derivatives on 3‐aminopropyl silica gel. The swelling capacity of the chitin derivatives, enantioseparation capability, as well as eluents tolerance of the chiral stationary phases were evaluated. The results demonstrated no remarkable difference in enantioseparation capability between natural and regenerated chitins based chiral stationary phases. The similar enantioseparation characteristics of two chiral stationary phases could be understood by comparing the IR spectra of related chitin derivatives. The one of the two chiral stationary phases prepared by coating the chitin derivative with a lower molecular weight generally provided better enantioseparations. All chiral stationary phases can work in 100% chloroform, 100% ethyl acetate, 100% acetone, and the mobile phases containing a certain amount of tetrahydrofuran. The chiral stationary phase prepared from the chitin derivative with the highest swelling capacity exhibited better enantioseparations than others. This chiral stationary phase was damaged by flushing with 100% tetrahydrofuran, however, the enantioseparation capability was recovered again after the column was allowed to stand for 1 month. Furthermore, the recovered chiral stationary phase provided better enantioseparations for some chiral analytes than before.     

Optimization of the LC enantioseparation of chiral pharmaceuticals using cellulose tris(4‐chloro‐3‐methylphenylcarbamate) as chiral selector and polar non‐aqueous mobile phases

The resolving power of a new commercial polysaccharide‐based chiral stationary phase, Sepapak‐4, with cellulose tris(4‐chloro‐3‐methylphenylcarbamate) coated on silica microparticles as chiral selector, was evaluated toward the enantioseparation of ten basic drugs with widely different structures and hydrophobic properties, using ACN as the main component of the mobile phase. A multivariate approach (experimental design) was used to screen the factors (temperature, n‐hexane content, acidic and basic additives) likely to influence enantioresolution. Then, the optimization was performed using a face‐centered central composite design. Complete enantioseparation could be obtained for almost all tested chiral compounds, demonstrating the high chiral discrimination ability of this chiral stationary phase using polar organic mobile phases made up of ACN and containing an acidic additive (TFA or formic acid), 0.1% diethylamine and n‐hexane. These results clearly illustrate the key role of the nature of the acidic additive in the mobile phase.     

高效液相色谱法直接测定几种非甾体类解热镇痛药物中的对映体含量

用WHELK-O1手性色谱柱，在正相条件下测定了几种非甾体类解热镇痛药物萘普生、布洛芬、酮基布洛芬和苯氧布洛芬等中对映体的含量。结果表明：这种手性固定相色谱柱能够以正己烷和异丙醇为流动相，简便、快速、准确地测定非甾类药物中对映体的含量。     

Chiral separation of beta-adrenergic antagonists, profen non-steroidal anti-inflammatory drugs and chlorophenoxypropionic acid herbicides using teicoplanin as the chiral selector in capillary liquid chromatography

Three groups of structurally diverse chiral compounds were used to study the interaction mechanism responsible for stereoselective recognition with teicoplanin as chiral selector in capillary liquid chromatography. Teicoplanin-based chiral stationary phase (CSP) was used. The effect of the variation of mobile phase composition on retention and enantioselective separation was studied. The mobile phase composition suitable for enantioresolution of the various chiral compounds differed according to the interaction forces needed for chiral recognition. Mobile phases with high buffer portion (70-90 vol.%) were preferred for separation of enantiomers of profen non-steroidal anti-inflammatory drugs and chlorophenoxypropionic acid herbicides that require hydrophobic interactions, inclusion and pi-pi interactions for stereoselective recognition with teicoplanin. Higher concentration triethylamine in the buffer (0.5-1.0%) increased resolution of these acids. On the other hand, H-bonding and electrostatic interactions are important in stereoselective interaction mechanism of beta-adrenergic antagonists with teicoplanin. These interaction types predominate in the reversed phase separation mode with high organic modifier content (95% methanol) and in polar organic mobile phases. For this reason beta-adrenergic antagonists were best enantioresolved in the polar organic mode. The mobile phase composed of methanol/acetic acid/triethylamine, 100/0.01/0.01 (v/v/v), provided enantioresolution values of all the studied beta-adrenergic antagonists in the range 1.1-1.9. Addition of teicoplanin to the mobile phase, which was suitable for enantioseparation of certain compounds on the CSP, was also investigated. This system was used to dispose of nonstereoselective interactions of analytes with silica gel support that often participate in the interaction with CSPs. Very low concentration of teicoplanin in the mobile phase (0.1 mM) resulted in enantioselective separation of 2,2- and 2,4-chlorophenoxypropionic acids.     

COVALENTLY BONDING CHIRAL POLYURETHANE ON AMINATED SILICA GEL： A NEW STRATEGY TO PREPARE CHIRAL STATIONARY PHASE FOR HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

Two polyurethanes of different molecular weights were prepared by the copolymerization of phenyl diisocyanate and diisopropyl tartrate. The polyurethanes having terminal isocyanate groups were reacted with 3-aminopropyl silica gel to afford two chiral stationary phases. The Mn of the two polyurethanes were 4057 g/mol and 6442 g/mol. The polyurethanes and the corresponding chiral stationary phases were characterized by FT-IR, 1H NMR and elemental analysis. The loading capacities of the polyurethanes on silica gel were 0.68 mmol units/g and 0.61 mmol units/g, respectively. The separation performance and the influence of additives, triethylamine and trichloroacetic acid, on the separation of chiral compounds were investigated by HPLC. The chiral stationary phase prepared from polyurethane with Mn of 4057 g/mol demonstrated better enantioseparation capability than that with Mn of 6442 g/mol. Additionally, it was found that the addition of triethylamine and trichloroacetic acid in the mobile phases significantly improved the enantioseparation for these two chiral stationary phases.     

高效液相色谱手性固定相法直接拆分4种吲哚类衍生物

将纤维素-三(3,5-二甲基苯基氨基甲酸酯)(CDMPC)涂敷于自制的球形氨丙基硅胶上,制备成了纤维素-三(3,5-二甲基苯基氨基甲酸酯)手性固定相(CDMPC-CSP)。利用正相高效液相色谱,在该固定相上对新合成的4种吲哚类衍生物对映体进行了手性拆分。通过选择不同结构和浓度的醇类改性剂,优化了色谱分离条件,同时探讨了醇的结构和浓度对于对映体拆分和保留的影响。结果表明,适合Ⅱ~Ⅳ号样品拆分的醇类改性剂分别为正丁醇、乙醇和乙醇,而适合Ⅰ号样品的醇类改性剂为乙醇和正丙醇组成的混合体系。在优化的各流动相体系下,4种吲哚类衍生物的对映体都得到了很好的分离。在此基础上计算了它们的对映体过量值(e.e.值)。实验结果令人满意,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。     

Enantioselective strong cation-exchange molecular recognition materials: design of novel chiral stationary phases and their application for enantioseparation of chiral bases by nonaqueous capillary electrochromatography

New chiral stationary phases derived from enantiomerically pure derivatives of cysteine carrying sulfonic acid groups are synthesized and evaluated for enantiomer separation of chiral bases by non aqueous capillary electrochromatography after bonding to a linker and grafting upon thiol-modified silica particles. Structural modifications of these low molecular weight chiral selectors are investigated and discussed in terms of apparent enantioselectivities and resolution factors based on the enantiomeric separations of a set of chiral bases including beta-blockers, beta-sympathomimetics and other basic drugs. The influence of the mobile phase constitution and its flow velocity on the enantioseparation by nonaqueous capillary electrochromatography is also briefly evaluated and discussed for the chiral substances investigated.     

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.     

Use of tert-butylbenzoylated tartardiamide chiral stationary phase for the enantiomeric resolution of acidic compounds by nano-liquid chromatography

Several racemic acidic compounds of pharmaceutical and environmental interest have been separated into their enantiomers by nano-liquid chromatography (nano-LC) employing a tert-butylbenzoylated tartardiamide chiral stationary phase (CHI-TBB). CHI-TBB was packed into a fused silica capillary of 100 microm id and retained by two frits made with a heated wire; detection was on-column at a window (about 0.5 cm) prepared by removing the polyimide layer. The normal phase mode was selected for eluting the studied acidic compounds and therefore n-hexane/2-propanol/acetic acid (89/10/1, v/v/v) was used as mobile phase. Working at a flow rate of 220 nL/min a good resolution was obtained for mecoprop, dichlorprop, diclofop, fenoxaprop (herbicides) and for DF 1738Y, DF 1770Y, DF 2008Y (drugs under evaluation). In order to optimize the chiral resolution we modified the polarity of the mobile phase by adding several polar additives such as ethyl acetate, dichloromethane, tert-butyl methyl ether. Better results were obtained for some herbicides on working with 2-propanol/CH2Cl2/n-hexane/acetic acid (8/4/87/1, v/v/v/v). The influence of the capillary temperature on chiral resolution was studied for two herbicides with different chemical structures, namely mecoprop and haloxyfop in the temperature range between 10 and 40 degrees C and with n-hexane/2-propanol/1% acetic acid (89/10/1, v/v/v) as the mobile phase. Linear correlation of ln k vs 1/T and In alpha vs 1/ T was observed; deltaH degrees values were negative, demonstrating that retention of analytes was an exothermic process. A decrease in resolution was observed with rising temperature, showing that enantioresolution was mainly influenced by selectivity factors.     

Enantiomeric separation of chiral theophylline derivatives by liquid chromatography on cellulose-based sorbents

The enantiomeric resolution of seven closely related theophylline racemates by high-performance liquid chromatography on cellulose-based sorbents, in particular Chiralcel-OD, -OC and -OJ, is described. Although all chiral stationary phases (CSPs) are suitable for the enantioseparation of all racemates investigated, it is obvious that method development is different for each stationary phase. The screenings with the above-mentioned CSP included variation of mobile phase and temperature. It turned out that Chiralcel-OD should be used with 2-propanol in n-hexane as the mobile phase at higher temperatures, whereas Chiralcel-OC performed best with methanol at ambient temperature. Improved enantioseparations were observed for Chiralcel-OJ with increased modifier concentrations in n-hexane at increased temperature.     

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。