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1.
Qiu‐Yun Wang Ya‐Jin Xiong Bao‐Zhu Lu Jun Fan Sheng‐Run Zheng Wei‐Guang Zhang 《Chirality》2013,25(9):487-492
Twelve chiral compounds were enantiomerically resolved on bovine serum albumin chiral stationary phase (BSA‐CSP) by high‐performance liquid chromatography (HPLC) in reversed‐phase modes. Chromatographic conditions such as mobile phase pH, the percentage of organic modifier, and concentration of analyte were optimized for separation of enantiomers. For N‐(2, 4‐dinitrophenyl)‐serine (DNP‐ser), the retention factors (k) greatly increase from 0.81 to 6.23 as the pH decreasing from 7.21 to 5.14, and the resolution factor (Rs) exhibited a similar increasing trend (from 0 to 1.34). More interestingly, the retention factors for N‐(2, 4‐dinitrophenyl)‐proline (DNP‐pro) decrease along with increasing 1‐propanol in mobile phase (3%, 5%, 7% and 9% by volume), whereas the resolution factor shows an upward trend (from 0.96 to 2.04). Moreover, chiral recognition mechanisms for chiral analytes were further investigated through thermodynamic methods. Chirality 25:487–492, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
2.
The aim of the paper is to describe a new synthesis route to obtain synthetic optically active clausenamidone and neoclausenamidone and then use high‐performance liquid chromatography (HPLC) to determine the optical purities of these isomers. In the process, we investigated the different chromatographic conditions so as to provide the best separation method. At the same time, a thermodynamic study and molecular simulations were also carried out to validate the experimental results; a brief probe into the separation mechanism was also performed. Two chiral stationary phases (CSPs) were compared with separate the enantiomers. Elution was conducted in the organic mode with n‐hexane and iso‐propanol (IPA) (80/20 v/v) as the mobile phases; the enantiomeric excess (ee) values of the synthetic R‐clausenamidone and S‐clausenamidone and R‐neoclausenamidone and S‐ neoclausenamidone were higher than 99.9%, and the enantiomeric ratio (er) values of these isomers were 100:0. Enantioselectivity and resolution (α and Rs, respectively) levels with values ranging from 1.03 to 1.99 and from 1.54 to 17.51, respectively, were achieved. The limits of detection and quantitation were 3.6 to 12.0 and 12.0 to 40.0 ug/mL, respectively. In addition, the thermodynamics study showed that the result of the mechanism of chiral separation was enthalpically controlled at a temperature ranging from 288.15 to 308.15 K. Furthermore, docking modeling showed that the hydrogen bonds and π‐π interactions were the major forces for chiral separation. The present chiral HPLC method will be used for the enantiomeric resolution of the clausenamidone derivatives. 相似文献
3.
《Chirality》2017,29(1):19-25
The enantiomeric separation of the enantiomers of three phenylpyrazole pesticides (fipronil, flufiprole, ethiprole) and two fipronil metabolites (amide‐fipronil and acid‐fipronil) were investigated by high‐performance liquid chromatography (HPLC) with a CHIRALPAK® IB chiral column. The mobile phase was n‐ hexane or petroleum ether with 2‐propanol or ethanol as modifier at a flow rate of 1.0 mL/min. The influences of mobile phase composition and column temperature between 15 and 35°C on the separations were studied. All the analytes except ethiprole obtained complete enantiomeric separation after chromatographic condition optimization. Fipronil, flufiprole, amide‐fipronil, and acid‐fipronil obtained complete separation with the best resolution factors of 2.40, 3.40, 1.67, and 16.82, respectively, but ethiprole showed no enantioselectivity under the optimized conditions. In general, n‐ hexane with 2‐propanol gave better separations in most cases. The results showed decreasing temperature and content of modifier in the mobile phase resulted in better separation and longer analysis time as well. The thermodynamic parameters calculated according to linear the Van't Hoff equation indicated the chiral separations in the study were enthalpy‐driven. Fipronil and its two chiral hydrolyzed metabolites obtained baseline separation simultaneously under optimized conditions. 相似文献
4.
An optical resolution of the amide derivatives of ibuprofen and the carbamate-alkylester derivatives of the trans-alcohol metabolite of loxoprofen and an analogous compound, CS-670, was studied by chiral high-performance liquid chromatography (HPLC). The chiral columns SUMIPAX OA-4000 and OA-4100 were used to investigate the enantiomeric separation behavior of these derivatives using both reversed and normal mobile phases. A better separation factor (α) of the amide and the carbamate ester derivatives was obtained in the normal mobile phase than in the reversed mobile phase HPLC. In addition, the recognition mechanisms of both amide and carbamate ester enantiomers were investigated by 1H-nuclear magnetic resonance (NMR). It is suggested that the important driving forces for the enantiomeric separation are the formation of hydrogen bonding and the charge transfer complex between these derivatives and an active site of the chiral stationary phase. © 1995 Wiley-Liss, Inc. 相似文献
5.
Four chiral stationary phases (CSPs) derived from N-(3,5-dinitrobenzoyl)tyrosine have been synthesized. They differ by the substituent nature (methyl, ethyl, isopropyl, tert-butyl) of the aliphatic amide function. The enantiorecognition ability of these CSPs was evaluated with 10 racemates. For the majority of them, the stereoselectivity increases with the steric hindrance of the substituent. The chiral selector enantiomeric separation on the resulting CSPs has evidenced a reversal of elution order only for CS 4 on CSP 4 (tert-butyl substituent), suggesting a change in its conformation. 相似文献
6.
Preparation and Studies of Chiral Stationary Phases Containing Enantiopure Acridino‐18‐Crown‐6 Ether Selectors
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Tamás Németh Sándor Lévai Attila Kormos József Kupai Tünde Tóth György Tibor Balogh Péter Huszthy 《Chirality》2014,26(10):651-654
The enantiomeric separation ability of the newly prepared chiral stationary phases containing acridino‐18‐crown‐6 ether selectors was studied by high‐performance liquid chromatography (HPLC). The chiral stationary phases separated the enantiomers of selected protonated primary aralkylamines efficiently. The best results were found for the separation of the mixtures of enantiomers of NO2‐PEA. Chirality 26:651–654, 2014. © 2014 Wiley Periodicals, Inc. 相似文献
7.
Yi Jun Zhang Ming Xian Huang Yu Ping Zhang Daniel Wayne Armstrong Zachary S. Breitbach Jae Jeong Ryoo 《Chirality》2013,25(11):735-742
Sulfated cyclofructan 6 (S‐CF6) and sulfated cyclodextrins (S‐α‐, β‐, γ‐CDs) are highly selective chiral selectors for the enantioseparation of basic solutes. In this study, S‐CF6 was introduced for the enantiomeric separation of four basic pharmaceuticals (including tamsulosin, tiropramide, bupivacaine, and norephedrine) by capillary electrophoresis (CE), and the enantiomeric separation performance was compared with S‐α‐, β‐, γ‐CDs. The effects of the chiral selector type, chiral selector concentration, operating voltage, and column temperature were examined and optimized. Excellent resolutions were obtained for all solutes on these chiral selectors. Chirality 25:735–742, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
8.
Lutz Sulimma Anke Bullach Souvik Kusari Marc Lamshöft Sebastian Zühlke Michael Spiteller 《Chirality》2013,25(6):336-340
For almost four decades, the chiral fungicides metalaxyl and furalaxyl have been in use in plant protection on a global scale. Both substances are distributed as racemic mixtures, yet the desirable interference in nucleic acid synthesis of harmful fungi only occurs by the (‐)‐R‐enantiomer. As enantioselective degradation in Scheyern (Germany) and Yaoundé (Cameroon) soils has been documented, the influence of 50 isolated microorganisms on the R/S ratio was investigated. A high‐pressure liquid chromatography method with a chiral column to separate enantiomers of metalaxyl and furalaxyl, and subsequent detection by tandem mass spectrometry, was employed. Only one of these microorganisms, a strain of Brevibacillus brevis, showed an enantioselective degradation pattern in liquid culture; the respective (‐)‐R‐enantiomers were preferably degraded. Moreover, (‐)‐R‐furalaxyl was degraded faster in cultures supplemented simultaneously with both fungicides of the same concentration. Chirality 25:336–340, 2013. © 2013 Wiley‐Liss Inc. Chirality 00:000‐000:, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
9.
Assignment of absolute configuration to a recently developed chiral selector useful in the separation of the underivatized enantiomers of naproxen and other nonsteroidal anti-inflammatory drugs (NSAIDs) is described. Circular dichroism, 1H NMR, and X-ray diffraction have been used to confirm the original assignment which was based solely upon elution orders from HPLC chiral stationary phases. All of these techniques agree in the assignment of the (S,S) absolute configuration to the enantiomer of the chiral selector which associates preferentially with (S)-naproxen. © 1994 Wiley-Liss, Inc. 相似文献
10.
《Chirality》2017,29(7):386-397
Chiral resolution of baclofen, bupropion, and etodolac profens was obtained with amylose derivatized chiral reversed stationary phase (carbamate groups). The eluent used for bupropion and etodolac was MeOH–water (20:80, v /v) and for baclofen was water–methanol (95:5, v /v). The eluent run rates, finding wavelength and temperature, were 1.0 mL/min, 220 nm and 27 ± 1 °C for all the eluents. The magnitude of the retardation factors for S‐ and R‐enantiomers of baclofen, bupropion, and etodolac were 1.37, 2.62, 2.25, 3.25, 1.8, and 3.0. The magnitudes of separation and resolution factors were 1.90, 1.44, and 1.67 and 2.77, 2.35, and 2.04. Limits of detection and quantitation were 1.0–2.0 and 5.1–10.0 μg/mL. Chiral recognition mechanisms were recognized by simulation and high‐performance liquid chromatography (HPLC) experiments. It was seen that hydrogen interactions, hydrophobic interactions, and π–π exchanges were the chief interactions for chiral recognition mechanisms. The described methods may be exploited for the chiral separation of baclofen, bupropion, and etodolac profens in any unknown sample. 相似文献
11.
Optically active lumazines (biolumazine, dictyolumazine, monalumazine, and neolumazine) are prepared from the corresponding pterins by enzymatic reaction, using pterin deaminase excreted by Dictyostelium discoideum. The fluorescence properties, circular dichroism spectra, and chromatographic behavior of these lumazines are studied. D - and L -enantiomers of biolumazine, dictyolumazine, and monalumazine are separated using a chiral flavoprotein column. This column also separates the enantiomeric pterins of the threo form: monapterin and dictyopterin. However, the column does not separate the enantiomeric pterins of the erythro form: neopterin and biopterin. By coupling a reverse-phase column to the flavoprotein column, the separation of pterins and lumazines in function of their hydrophobicity, as well as the separation of the diastereomers, is achieved. This coupled achiral/chiral high-performance liquid chromatography method enables determination of the stereoconfiguration of natural lumazines by comparison with optically pure compounds. A lumazine derivative, present in the extracellular medium of Dictyostelium discoideum, is identified as D -dictyolumazine, i.e., 6-(D -threo-1,2-dihydroxypropyl)-lumazine. © 1994 Wiley-Liss, Inc. 相似文献
12.
Carla Fernandes Andreia Palmeira Alexandre Santos Maria Elizabeth Tiritan Carlos Afonso Madalena M. Pinto 《Chirality》2013,25(2):89-100
The resolution of seven enantiomeric pairs of chiral derivatives of xanthones (CDXs) on (S,S)‐Whelk‐O1 and l ‐phenylglycine chiral stationary phases (CSPs) was systematically investigated using multimodal elution conditions (normal‐phase, polar‐organic, and reversed‐phase). The (S,S)‐Whelk‐O1 CSP, under polar‐organic conditions, demonstrated a very good power of resolution for the CDXs possessing an aromatic moiety linked to the stereogenic center with separation factor and resolution factor ranging from 1.91 to 7.55 and from 6.71 to 24.16, respectively. The chiral recognition mechanisms were also investigated for (S,S)‐Whelk‐O1 CSP by molecular docking technique. Data regarding the CSP–CDX molecular conformations and interactions were retrieved. These results were in accordance with the experimental chromatographic parameters regarding enantioselectivity and enantiomer elution order. The results of the present study fulfilled the initial objectives of enantioselective studies of CDXs and elucidation of intermolecular CSP–CDX interactions. Chirality 25:89–100, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
13.
Tohru Taniguchi Mai Asahata Akihito Nasu Yukatsu Shichibu Katsuaki Konishi Kenji Monde 《Chirality》2016,28(7):534-539
Separation of the diastereomers of glycosyl sulfoxides differing in the sulfur chirality has been difficult. This article presents a fast and scalable method for their diastereoseparation using a chiral stationary phase. The usefulness of this method was demonstrated in a 500‐mg scale separation within 20 min, and in the separation of trisaccharyl sulfoxide diastereomers. Chirality 28:534–539, 2016. © 2016 Wiley Periodicals, Inc. 相似文献
14.
Cyclodextrin‐Functionalized Monolithic Capillary Columns: Preparation and Chiral Applications
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In this review, the recently reported approaches for the preparation of cyclodextrin‐functionalized capillary monolithic columns are highlighted, with few applications in chiral separations using capillary liquid chromatography (CLC) and capillary electrochromatography (CEC). Chirality 28:97–109, 2016. © 2015 Wiley Periodicals, Inc. 相似文献
15.
With the aim to define a combined computational/chromatographic empirical approach useful for the high‐performance liquid chromatography (HPLC) method development of new chiral compounds, 36 racemic aromatic compounds with different chemical structures were used as test probes on four polysaccharide‐based chiral stationary phases (CSPs) of the Lux series, namely Lux Cellulose‐1, Lux Cellulose‐2, Lux Cellulose‐4, and Lux Amylose‐2, using classical n‐hexane/2‐propanol mixtures as mobile phase. Electrostatic potential surfaces (EPSs) determined using Density Functional Theory (DFT) calculations were used to derive size, shape, and electronic properties of each analyte. Then a comparative HPLC screening was carried out in order to evaluate the impact of substituents, shapes, and electronic properties of the analytes on the chromatographic behavior as the column changes. The four CSPs showed good complementary recognition ability. The elution sequence was determined in 30 cases out of 36. The success rate to afford baseline separations (Rs ≥ 1.5) was estimated: 29 compounds out of 36 showed baseline enantioseparation on at least one of the four selected CSPs. The combined computational‐chromatographic screening furnished useful collective structure‐chromatographic behavior relationships and a map of the chiral discrimination abilities of the considered CSPs towards the analytes. On this basis, the chromatographic behavior of new analytes on a set of polysaccharide‐based CSPs can be mapped through the qualitative correlation of chromatographic parameters (k, α, Rs) to computed molecular properties of the analytes. Chirality 25:709–718, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
16.
The drug chirality is attracting increasing attention because of different biological activities, metabolic pathways, and toxicities of chiral enantiomers. The chiral separation has been a great challenge. Optimized high‐performance liquid chromatography (HPLC) methods based on vancomycin chiral stationary phase (CSP) were developed for the enantioseparation of propranolol, atenolol, metoprolol, venlafaxine, fluoxetine, and amlodipine. The retention and enantioseparation properties of these analytes were investigated in the variety of mobile phase additives, flow rate, and column temperature. As a result, the optimal chromatographic condition was achieved using methanol as a main mobile phase with triethylamine (TEA) and glacial acetic acid (HOAc) added as modifiers in a volume ratio of 0.01% at a flow rate of 0.3 mL/minute and at a column temperature of 5°C. The thermodynamic parameters (eg, ΔH, ΔΔH, and ΔΔS) from linear van 't Hoff plots revealed that the retention of investigated pharmaceuticals on vancomycin CSP was an exothermic process. The nonlinear behavior of lnk′ against 1/T for propranolol, atenolol, and metoprolol suggested the presence of multiple binding mechanisms for these analytes on CSP with variation of temperature. The simulated interaction processes between vancomycin and pharmaceutical enantiomers using molecular docking technique and binding energy calculations indicated that the calculated magnitudes of steady combination energy (ΔG) coincided with experimental elution order for most of these enantiomers. 相似文献
17.
Prothioconazole is a type of broad‐spectrum triazole thione fungicide developed by the Bayer Company. Prothioconazole‐desthio is the main metabolite of prothioconazole in the environment. In our study, enantiomeric separation of prothioconazole and prothioconazole‐desthio was performed on various chiral stationary phases (CSPs) by high‐performance liquid chromatography (HPLC). It was found that polysaccharide CSPs showed better ability than brushing CSPs in enantiomeric separation. The successful chiral separation of prothioconazole could be achieved on self‐made Chiralcel OD, commercialized Chiralcel OJ‐H and Lux Cellulose‐1. Chiralpak IA, Chiralpak IB, Chiralpak IC, Chiralcel OD, Chiralpak AY‐H, Chiralpak AZ‐H, and Lux Cellulose‐1 realized the baseline separation of prothioconazole‐desthio enantiomers. Simultaneous enantiomeric separation of prothioconazole and prothioconazole‐desthio was performed on Lux Cellulose‐1 using acetonitrile (ACN) and water as mobile phase. In most cases, low temperature favored the separation of two compounds. The influence of the mobile phase ratio or type was deeply discussed. We obtained larger Rs and longer analysis time with a smaller proportion of isopropanol (IPA) or ethanol and more water content at the same temperature. The ratio of ACN and water had influences on the outflow orders of prothioconazole‐desthio enantiomers. This work provides a new approach for chiral separation of prothioconazole and prothioconazole‐desthio with a discussion of chiral separation mechanism on different CSPs. 相似文献
18.
19.
The separation of the four nadolol stereoisomers on Chiralpak® AD by chiral liquid chromatography was carried out at both analytical and preparative scales. A screening of possible mobile‐phase compositions was performed using different alcohol–hydrocarbon mixtures. The results obtained confirm the use of 20:80:0.3 ethanol‐hexane‐diethylamine reported by McCarthy (1994) but introduce other possibilities for the complete resolution of the four nadolol stereoisomers at analytical scale, namely, the mixtures 30–40:70–60:0.3 ethanol‐heptane‐diethylamine. Additionally, this work describes how retention and resolution depend on the ethanol content in hexane and heptane mixtures. The separation of nadolol stereoisomers is also carried out at preparative scale and different alcohol–hydrocarbon compositions are proposed, depending on the target component to be obtained. Particularly, this work presents the experimental separation of the more retained nadolol stereoisomer (RSR‐nadolol) by simulated moving bed (SMB) chromatography using an 80:20:0.3 ethanol‐heptane‐diethylamine mobile phase. For a 2 g/l feed concentration, RSR‐nadolol is 100% recovered at the extract outlet stream, 100% pure, and with a system productivity of 0.65 gRSR‐nadolol/(lbed.h) and a solvent consumption of 9.6 lsolvent/gRSR‐nadolol. Chirality 25:197–205, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
20.
A strategy based on the use of homo bi- and multifunctional building blocks for the synthesis of a new class of network-polymeric chiral stationary phases has been evaluated. The key steps comprise acylation of N,N′-diallyl-L-tartardiamide (DATD) and reaction with a multifunctional hydrosilane, yielding a network polymer incorporating the bifunctional C2-symmetric chiral selector. Covalent bonding to a functionalized silica takes place during the latter process. Many of these chiral sorbents show interesting enantioselective properties toward a wide variety of racemic solutes under normal-phase (hexane-based) conditions. The retention is mainly caused by the hydrogen-bonding ability of the analyte, which is regulated by mobile phase additives like alcohol or ether cosolvents. The most interesting chiral stationary phases, in terms of broad enantioselectivity, were obtained from O,O′-diaryol-DATD-derivatives, particularly those containing the 3,5-dimethylbenzoyl and the 4-(tert-butyl)benzoyl moieties. Since high column efficiencies can be obtained with these chiral sorbents, an α-value of ca. 1.2 is usually sufficient to produce baseline separation. A large number of neutral as well as acidic or basic drug racemates are resolved without derivatization. © 1995 Wiley-Liss, Inc. 相似文献