锆基纤维素手性固定相直接拆分萘普生衍生物

萘普生是一种消炎镇痛药 ,其 S对映体的抗炎作用是 R构型的 2 8倍 ,萘普生及其衍生物的拆分具有重要意义 .手性固定相 HPLC直接拆分 [1～ 4 ] 是最简便的分析方法 .氧化锆是近年来备受关注的色谱载体 [5,6 ] .Carr等 [7] 对碱性药物快速拆分表明氧化锆在手性分离Scheme1　 Structuresof chiral naproxen and its derivatives中的独特选择性 .萘普生及其衍生物在锆基手性固定相上的分离未见文献报道 .本组利用自制的球形氧化锆制备了涂敷型纤维素 -三 ( 3,5 -二甲基苯基氨基甲酸酯 ) -Zr O2 手性固定相 ( CDMPC- Zr O2 - CSP) ,在正…     

Enantioseparation of vesamicol and novel vesamicol analogs by high-performance liquid chromatography on different chiral stationary phases

High-performance liquid chromatography enantioseparation of vesamicol and six novel azaspirovesamicols (amino alcohols) was accomplished on different chiral stationary phases (CSPs) by using an optical rotation based chiral detector for identification of the resolved enantiomers. The Pirkle-type column Reprosil Chiral-NR was found to be most suitable for chiral resolution in normal phase (NP) mode; all compounds could be enantioseparated successfully. Also the cellulose-based column Reprosil Chiral-OM showed appropriate separation properties by using NP conditions. The amylose-type column Reprosil Chiral-AM-RP was most suitable for enantioseparation in reversed phase (RP) mode; five out of seven compounds were resolved. This CSP showed a considerably higher capability for chiral recognition of vesamicol derivatives in RP mode than the corresponding cellulose-based column Reprosil Chiral-OM-RP. Enantioseparation with the teicoplanin aglycone-based column Reprosil Chiral-AA was successful under polar ionic mobile phase conditions.     

Selection of the Mobile Phase for Enantiomeric Resolution via Chiral Stationary Phase Columns

Abstract

The optimization of enantiomeric resolution by mobile phase variation was studied with the chiral stationary phase derived from R-N-(3,5-dinitrobenzoyl) phenylglycine covalently coupled to 5 μm spherical 3-aminopropyl silica. Chromatography was routinely performed with mobile phase compositions having polarities as high as 2.5 without column deterioration. The relative strength of a solvent as a hydrogen acceptor was found to be an important basis for selection of the polar component in a binary mobile phase. The substitution of tert-butanol for 2-propanol or ethanol in an alcohol/hexane mixture, for example, afforded improved separation factors with several enantiomers. In addition, the need for a polar mobile phase such as 50/50 methylene chloride/hexane to minimize non-specific polar absorption of enantiomers has been demonstrated. Enhancement of specific chiral interactions and suppression of interfering reactions have been obtained with a number of clinically relevant derivatives as model compounds.     

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.     

Influence of structure and chirality of the selector on the chiral recognition of amino acids using ligand-exchange capillary electrophoresis

The dependence of the chiral recognition ability and enantiomer migration order on the structure, substitution pattern and chirality of chiral selectors used in ligand-exchange capillary electrophoresis is investigated. As chiral selectors different N-alkyl derivatives of proline and hydroxyproline as their copper(II) complexes are used. The influence of the position and conformation of the hydroxy group in the hydroxyproline derivatives and of the structure and chirality of the side chain on enantioselectivity is investigated. Furthermore, the effect of surfactants such as sodium dodecyl sulfate and cetyl trimethyl ammonium bromide on resolution and enantiomer migration order is studied. The investigations were carried out with three aromatic amino acids as model compounds.     

endo-1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2-carboxylic acid, a superior resolving agent for the high-performance liquid chromatographic separation of enantiomers of hydroxylated derivatives of two azaaromatic hydrocarbons

The high-performance liquid chromatographic (HPLC) separation of enantiomers of oxide and hydroxy derivatives of dibenz[a,j]acridine and 7-methylbenz[c]acridine was investigated on a chiral stationary phase chromatography column using commercially available columns. In most cases either poor or no separation of enantiomers was achieved. Normal-phase separation of diastereoisomeric ester derivatives of the hydroxy compounds, prepared from commercially available (-)-menthoxyacetic acid or (+)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetic acid, was investigated. No separation of the diastereoisomeric esters of trans-3,4-dihydroxy-3,4-dihydrodibenz[a,j]acridine was observed. However, diastereoisomeric esters prepared from (+)-endo-1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2-carboxyl ic acid [(+)-HCA] were easily separated. Using the three chiral acids, diastereoisomers were prepared from sixteen hydroxy derivatives of dibenz[a,j]acridine and 7-methylbenz[c]acridine. (+)-HCA esters gave good to excellent HPLC separations which were superior to those achieved using other chiral acids in most cases. The enantiomeric composition of trans-3,4-dihydroxy-3,4-dihydrodibenz[a,j]acridine formed as a major rodent liver microsomal metabolite of dibenz[a,j]acridine was determined using (+)-HCA.     

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.     

Enantioseparation of Racemic Naproxen Esters on Cellulose Tris（4—methylbenzoate） Chiral Stationary Phase

Several kinds of racemic naproxen ester were successfully separated on CTMB chiral stationary phase with hexane-ethanol(98:2,vol./vol.) as the mobile phase. The influence of mobile phase composition and structure of racemic naproxen ester on chiral separation was studied and the chiral recognition mechanism of CTMB was discussed.     

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.

     

液相色谱分析AEE788对映体纯度

在Chiralcel OD-H色谱柱上,采用正己烷与异丙醇或乙醇为流动相,对AEE788对映体进行了拆分,考察了流动相组成、柱温和流速等条件对拆分效果的影响。结果表明,AEE788对映体在正己烷-异丙醇-二乙胺(75:25:0.15,V/V/V)为流动相、柱温25℃、流速1.0 mL/min条件下,分离度为1.85,分析时间小于12 min。该分析方法的建立对药物AEE788不对称反应研究、分析/分离方法的开发及其生产过程的质量监控都具有非常重要的意义。     

Enantiomeric Separation of N-Protected Non-Protein Amino Acid Esters by Chiral High-Performance Liquid Chromatography

Abstract

We have found that high-performance liquid chromatographic analysis of enantiomeric N-protected amino acid esters on a cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase column (Daicel Chiralcel OD) can be utilized as one of the procedures for determining the optical purities of non-protein amino acids. The methyl esters of the N-benzyloxycarbonyl (Z) derivatives of a number of non-protein amino acids showed excellent to good enantiomeric separations using hexane - 2-propanol as a mobile phase. There was a regularity in the elution order of enantiomers: the L-isomer had a shorter retention time than the D-isomer. We have also investigated the effect of the N-protecting groups and the ester groups on the enantiomeric separation. The Z, 4-methoxybenzyloxycarbonyl (Z(OMe)), and 9-fluorenylmethoxycarbonyl (Fmoc) derivatives gave exceptionally good resolutions. By contrast, the formyl and t-butoxycarbonyl (Boc) groups impaired the enantiomeric separation. Almost all the alkyl esters examined and the benzyl ester gave resolutions better than or of the same order as the methyl ester. The resolution of β-amino acids was worse than that of the corresponding α-amino acids.     

Use of an o-Benzyl-(S)-Serine Containing Eluent for the Efficient Ligand-Exchange Chromatography-Based Enantioseparation of Constrained Glutamate Receptor Ligands

Four dihydroisoxazole prolines and four dihydroisoxazole cyclopentane derivatives were submitted to chiral ligand-exchange chromatographic analysis in the presence of O-benzyl-(S)-serine, as the chiral mobile phase additive to the eluent. The 1.0 mM O-benzyl-(S)-serine and 0.5 mM Cu(NO₃)₂ eluent flowed at 1.0 mL/min through a conventional octadecylsilica-based stationary phase maintained at 25°C and provided excellent levels of enantioselectivity and resolution for all the species. By using enantiomers as model compounds, the method was validated revealing that the mixed ternary diastereomeric eluates present slightly different spectroscopic properties. The selected chiral ligand-exchange chromatography method was applied for semi-preparative enantioisolation that allowed the establishment of the k(?) < k(+) enantiomeric elution order.     

Dress-up chiral columns for the enantioseparation of amino acids based on fluorous separation

In this paper, we report a new type of chiral high-performance liquid chromatography (HPLC) column—a so-called dress-up chiral column—featuring a chiral stationary phase adsorbed reversibly in a commercial fluorous HPLC column through fluorous interactions. We synthesized perfluroalkylated proline derivatives as chiral stationary phase compounds and then adsorbed them reversibly in the fluorous HPLC column through the pumping of their solutions. By using this dress-up chiral column and fluorophobic elution of an aqueous copper(II) sulfate/MeOH mixture, we could enantioseparate seven racemic amino acids within 40 min. When we washed the dress-up chiral column with fluorophilic tetrahydrofuran or MeOH, the adsorbed chiral stationary phase compounds desorbed from the column, completely destroying its enantioseparation ability. The relative standard deviation of the retention times, the number of theoretical plates, and the resolution for each of four preparations of the dress-up columns were all less than or equal to 9.53 % in 20-times repeated analysis, and were all less than or equal to 18.7 % in four different preparations, respectively.     

Enantioseparation of Binaphthol and Its Derivatives on Cellulose Tris(3,5-dimethylphenyl carbamate)

A Chiralcel OD-H column was used for the normal phase enantioseparation of binaphthol and its derivatives. Unexpectedly, binaphthol and its dibromo-substituted analogue could not be enantioseparated fully, whereas its ether and ester derivatives gave complete or partial resolution. Aspects of the chiral recognition are discussed further through calculated thermodynamic parameters.     

Analytical and semi-preparative HPLC enantioseparation of novel pyridazin-3(2H)-one derivatives with α-aminophosphonate moiety using immobilized polysaccharide chiral stationary phases

The direct HPLC enantioseparation of a novel series of chiral pyridazin-3(2H)-one derivatives with α-aminophosphonate moiety was performed on two immobilized polysaccharide chiral stationary phases (Chiralpak IA, Chiralpak IC) using n-hexane (n-Hex)/dichloromethane (DCM) mobile phase with 5% alcohol additive. Good baseline separation of the enantiomers was achieved using amylose tris-(3,5-dimethylphenylcarbamate) chiral stationary phases (Chiralpak IA) on analytical scale. The analytical method was further scaled up to semi-preparative loading to obtain small amounts of both the enantiomers of pyridazin-3(2H)-one derivative. The semi-preparative resolution of all compounds was successfully achieved with n-hexane/dichloromethane/ethanol (EtOH) as mobile phase using a semi-preparative Chiralpak IA column. The first fractions were isolated with purities of >99.9% (enantiomeric excess (e.e.), and the second fractions were obtained with purities of >98.2% (enantiomeric excess). The assignment of the absolute configuration was established for the F1 fraction of compound a-2 by single-crystal X-ray diffraction method.     

Evaluation of triproline and tri-α-methylproline chiral stationary phases: Retention and enantioseparation associated with hydrogen bonding

In this study, to demonstrate preparation strategy and improve understanding of chiral recognition mechanisms, triproline chiral stationary phases (CSPs) were evaluated with a series of analytes classified as having none, one, two or three H-bond donors. The average retention factors and mobile phase strength generally followed none < one < two < three hydrogen bond donors. The average solvent volume ratio (H_r stands for average hexane volume ratio in the mobile phase, Hp_r for heptane, ACN_r for acetonitrile, or H₂O_r for water) normalized chromatographic parameters calculated for di-, tri-, tetra-, penta-, hexa-, and decaproline CSPs facilitated the characterization of properties associated to the H-bond donor categorization. The H_r of triproline CSP were 1.0, 0.96 and 0.88 for analyte of none, one and two hydrogen bond donors with hexane/2-propanol mobile phase, respectively. The number of hydrogen bond donors in an analyte was found to be a primary factor in influencing the retention and enantioseparation in the normal-phase and polar organic modes. Two H-bond acceptor solvents methyl tert-butyl ether and ethyl acetate increased chiral separation on oligoproline CSPs for some compounds. The role of carbon-donor hydrogen bonding at the H atom of proline asymmetric center was implied through testing a tri-α-methylproline stationary phase. On oligoproline CSPs, three factors including adjacent hydrogen bond acceptor and carbon-donor, and a rigid proline residue chain were recognized as important for contributing to the broad enantioselectivity. The α hydrogen atom on chiral center of stationary phase was found to play a crucial role in enantiomeric discrimination.     

纤维素三苯基氨基甲酸酯涂敷型固定相的制备及其对奥美拉唑的拆分

制备了纤维素三苯基氨基甲酸酯涂敷在自制的大孔氨丙基硅胶上的手性固定相，并对奥美拉唑进行了手性拆分。考察了流动相组成和流速对拆分效果的影响，发现用乙醇／正已烷作为流动相，手性物的分离度优于文献报道的异丙醇／正已烷流动相体系，适宜的流动相配比为乙醇／正已烷(40/60，V/V)。分离度随流动相中乙醇含量和流动相流速的增加而减小。     

2，6-二-O-乙氧乙基-3-O-三氟乙酰基-β-环糊精气相色谱手性固定相的制备及应用

将β-环糊精的2,6-位引入乙氧乙基,3-位引入三氟乙酰基,合成了新的环糊精衍生物2,6-二-O-乙氧乙基-3-O-三氟乙酰基-β-环糊精,并采用静态法涂渍毛细管气相色谱柱,考察了毛细管柱的柱性能和分离性能。结果表明,该固定相对G rob试剂、苯的二取代位置异构体氯甲苯、硝基甲苯和溴甲苯以及10种手性化合物如α-取代丙酸酯化合物、1-(2′-硝基苯基)-乙醇、α-甲基-对氯苯乙腈和丙炔醇酮乙酸酯等具有良好的分离效果。其中,对α-甲磺酰基丙酸酯对映体的拆分效果最好;对α-取代丙酸的甲酯衍生物的分离效果优于乙酯衍生物;对α-羟基取代丙酸酯的分离效果优于α-卤代丙酸酯。     

HPLC of fluoroquinolone antibacterials using chiral stationary phase based on enantiomeric (3,3′‐diphenyl‐1,1′‐binaphthyl)‐20‐crown‐6

A residual silanol group‐protecting chiral stationary phase (CSP) based on optically active (3,3′‐diphenyl‐1,1′‐binaphthyl)‐20‐crown‐6 was successfully applied to the resolution of fluoroquinolone compounds including gemifloxacin mesylate. The chiral recognition ability of the residual silanol group‐protecting CSP was generally greater than that of the residual silanol group‐containing CSP. From these results, it was concluded that the simple protection of the residual silanol groups of the latter CSP with lipophilic n‐octyl groups can improve its chiral recognition ability for the resolution of racemic fluoroquinolone compounds. The chromatographic resolution behaviors were investigated as a function of the content and type of organic and acidic modifiers and the ammonium acetate concentration in aqueous mobile phase and the column temperature. Especially, the addition of ammonium acetate to the mobile phase was found to be a quite effective means of reducing the enantiomer retentions without sacrificing the chiral recognition efficiency of the CSP.     

Separation of Enantiomers of N-Protected Non-Protein Amino Acid Esters by Chiral High-Performance Liquid Chromatography

The high-performance liquid chromatographic separation of enantiomers of N-protected non-protein amino acid esters was investigated by using a cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase column (Daicel Chiracel OD). The effect of the N-protecting groups and the ester groups on chiral discrimination was examined. The benzyloxycarbonyl (Z), 4-methoxybenzyloxycarbonyl, and 9-fluorenylmethoxycarbonyl derivatives gave good enantiomeric separations, while the formyl and t-butoxycarbonyl groups marred them. Almost all the alkyl esters examined and the benzyl ester gave enantiomeric separations better than or of the same order as the methyl ester. The N-Z-protected methyl esters of a number of non-protein -amino acids were well resolved using hexane–2-propanol as a mobile phase. The resolution of -amino acid derivatives was inferior to that of the isomeric -amino acid derivatives.