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The enantiomers of 1-phenyl-1,2,3,4-tetrahydroisoquinoline have been directly separated on polysaccharide-based chiral stationary phases (CSPs). The normal phase separation of (S)- and (R)-1-phenyl-1,2,3,4-tetrahydroisoquinoline was accomplished by screening of the immobilized Chiralpak IC column with different eluents. The effect of mobile phase type on retention, selectivity and resolution was studied. 2-Propanol or ethanol/n-hexane/ethanolamine mixtures were applied as mobile phases by screening of following polysaccharide-based immobilized (Chiralpak IA, Chiralpak IC) and coated (Lux Cellulose-1, Lux Cellulose-2, Lux Amylose-2) CSPs. Polar organic and reversed-phase conditions were also tested for direct enantioseparation of 1-phenyl-1,2,3,4-tetrahydroisoquinoline. 相似文献
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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. 相似文献
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Ismahan Rahou Nasser Belboukhari Khaled Sekkoum Abdelkarim Cheriti Hassan Y. Aboul-Enein 《Chromatographia》2014,77(17-18):1195-1201
The HPLC enantiomeric separation of seven 4-iminoflavans was successfully accomplished in the normal phase mode using six polysaccharide-based chiral stationary phases namely, Chiralcel®OD-H, Chiralcel®OD, Chiralcel®OJ, Chiralpak®AD, Chiralpak®IA and Chiralpak®IB under normal and polar organic phase modes. The resolution depended on nature and concentration of alcoholic modifier. The results demonstrate clearly that the chromatographic system based on the coated and immobilized type Chiralpak®IB and Chiralcel®OD-H CSPs provide a powerful analytical tool for enantiomeric separation of all the 4-iminoflavans used in this study. 相似文献
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Marianna Moskaľová Oleksandr Kozlov Taťána Gondová Mariana Budovská Daniel W. Armstrong 《Chromatographia》2017,80(1):53-62
A novel series of nine chiral analogs of spirobrassinin, which have potential biological activity, was separated for the first time on three different derivatized cyclofructan chiral stationary phases in the normal phase mode. The effects of mobile phase composition, the type and concentration of polar modifier, additives, and the analyte structure on the retention and enantioseparation were studied. The results proved that for cyclofructan-based chiral stationary phases, the R-naphthylethyl carbamate cyclofructan 6 provides the best separation efficiency for the analyzed compounds. The effect of temperature on the separation was also investigated and the corresponding thermodynamic parameters were evaluated from linear Van’t Hoff plots (lnk or lnα versus 1/T). It was found that the enantioseparation was enthalpy controlled. In addition, the elution order of the enantiomers was determined in all the cases. 相似文献
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Rahou Ismahan Belboukhari Nasser Sekkoum Khaled Cheriti Abdelkarim Aboul-Enein Hassan Y. 《Chromatographia》2014,77(17):1195-1201
The HPLC enantiomeric separation of seven 4-iminoflavans was successfully accomplished in the normal phase mode using six polysaccharide-based chiral stationary phases namely, Chiralcel®OD-H, Chiralcel®OD, Chiralcel®OJ, Chiralpak®AD, Chiralpak®IA and Chiralpak®IB under normal and polar organic phase modes. The resolution depended on nature and concentration of alcoholic modifier. The results demonstrate clearly that the chromatographic system based on the coated and immobilized type Chiralpak®IB and Chiralcel®OD-H CSPs provide a powerful analytical tool for enantiomeric separation of all the 4-iminoflavans used in this study.
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Srinivasu Gunnam Nagesh Kumar Kandukuri Ramachandra Bondigalla Thirupathi Choppari Lakshmi Narayana Chennuru Parameswara Murthy Cherla 《Chromatographia》2018,81(12):1705-1710
A group of DPP-4 inhibitors such as alogliptin, linagliptin and saxagliptin were selected for enantioseparation for this study. Crown ether columns contain a chiral crown ether ring as a chiral selector is suitable for the compounds having primary amino groups. Since the selected compounds contain free amino groups, a crown ether column was selected for enantiomeric separation of dipeptidyl peptidase-4 inhibitors. Dipeptidyl peptidase-4 inhibitors are a class of oral hypoglycemics that block dipeptidyl peptidase-4 enzyme and can be used to treat diabetes mellitus type 2. A sensitive HPLC method was developed to separate the enantiomers of each dipeptidyl peptidase-4 inhibitor. Effects of various parameters such as type of solvents, selection of additives, effect of pH and column temperature on chromatographic results were studied. The optimal conditions for the chiral separation of dipeptidyl peptidase-4 inhibitors without any derivatization were investigated. 相似文献
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A method for preparing a new polar substituted triazine stationary phase is described. The structure of the triazine phase on silica was characterized by elemental analysis, and by FTIR, solid state FT-13C NMR, and 29Si NMR spectral analysis. The chromatographic properties of this packing material have been evaluated by using a number of different solutes, and the properties compared with those of a commercial stationary phase RP-18. It is found that this triazine phase has weak π-donor ligands on the silica surface. 相似文献
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《Analytical letters》2012,45(16):2344-2358
Cyclodextrins (CDs) and cyclofructans (CFs) are chiral cyclic oligosaccharides. While β-CD is composed of seven glucopyranose units forming rigid cavity, hydrophobic inside, CF6 and CF7, contain six and seven fructofuranose units, respectively, creating a polar crown ether core. These basic structures can be easily derivatized to form even more potential chiral selectors that enable enantioselective separation of various chiral compounds. Chiral stationary phases (CSPs) based on CFs and CDs that were derivatized with the same derivatization group, either dimethylphenyl or R-naphthylethyl, were compared. A set of analytes with different interaction possibilities was used for characterization of retention and enantioseparation abilities of these CSPs in normal separation mode of HPLC. The results showed that both cyclic oligosaccharide structure and derivatization group influenced the retention/separation behavior of analytes. Complementary enantioseparations were obtained for some analytes. 相似文献
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Bixia Yao Guoqing Liu Shanshan Kang Cui Xiang Bei Huang Wen Weng Qingle Zeng 《Chromatographia》2011,74(7-8):625-631
Enantioseparation of 1,1??-bi-2-naphthol (BINOL) was performed on an immobilized polysaccharide-based chiral stationary phase (CSP), Chiralpak IA, in the normal-phase mode. The effects of polar modifier in the mobile phase and column temperature on retention, enantioseparation, and elution order were investigated. An interesting reversal of elution order for BINOL was observed. When ethanol was used as a polar modifier, R-BINOL was eluted first with marginal enantioseparation. Excellent enantioseparation was obtained when ethanol was replaced by 1-propanol, and S-BINOL was eluted first, this effect being retained with 2-butanol, 1-butanol, 1-pentanol or 1-hexanol as the modifier. When isoamyl alcohol was used, reversal of elution order was again observed, i.e., R-BINOL eluted first with marginal enantioseparation, similar to the case of ethanol. When cyclohexanol and cyclopentanol were used, R-BINOL was still eluted first, but enantioseparation was as good as with 1-propanol as the modifier. This is the first report of large enantioseparation obtained in both elution orders for a given selector/selectant system. A retention model based on stoichiometric displacement theory for retention (SDT-R) was investigated to fit the chromatographic data. The reason for solvent-induced reversal of elution order was elucidated based on a derivation of the retention model. Reversal of elution order for BINOL induced by the content of isoamyl alcohol was also predicted based on the model and confirmed by experiment. 相似文献
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应用三种大环抗生素类手性固定相Chirobiotic V、Chirobiotic T和Chirobiotic R,采用高效液相色谱法对盐酸克伦普罗对映体进行了拆分研究。实验考察了洗脱模式、流动相组成、柱温等因素对分离的影响,对分离结果进行了比较,并对其分离机制进行了探讨。结果表明,盐酸克伦普罗对映体在Chirobiotic R手性固定相上不能实现分离,在Chirobiotic V和Chirobiotic T手性固定相上,最佳色谱条件为:新极性有机相模式,流动相为甲醇-乙酸-三乙胺(100∶0.01∶0.01,V/V/V),流速:1.0mL/min,柱温:20℃,分离度可分别达到2.00和2.13。实验证明,盐酸克伦普罗对映体与大环抗生素类固定相之间的离子相互作用是实现对映体分离的最主要分离机制。 相似文献
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To develop photo-tunable chromatography, several azobenzene derivatives were immobilized or modified on silica gels or incorporated into polymers. The supports prepared were used as stationary phases in semi-micro HPLC, and the photo-dependence of their retention evaluated. On these stationary phases, the retention measured with 2-propanol in hexane was increased by UV irradiation; in contrast, the retention was decreased when methanol was used as mobile phase. It was assumed that the polarity of the stationary phase increases when the molecular structure of the azobenzene moieties changes from the trans to the cis form. On irradiation of the column with visible light after UV irradiation and with methanol as mobile phase, the change of retention proved to be reversible. However, this reverse change was less dramatic than the initial change. Such retention behavior is attributable to photo-isomerization of the azobenzene moieties. These findings will be exploited in our development of new photo-tunable stationary phases and new photo-controlled separation systems. 相似文献
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Introduction In recent years, chiral transition metal cluster has at-tracted a great deal of interests due to its potential ap-plication in asymmetric catalytic reaction.1-3 Producing catalysis for asymmetric induction using a rigid chiral framework would not only bring a basically conceptual breakthrough in the asymmetric catalysis, but also en-rich the methodology in the design of new chiral cata-lysts.4 So far, a lot of chiral clusters have been re-ported,5-9 but only a few of them have bee… 相似文献