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Experimental and computational spectroscopic studies of 3,5-disubstituted 4,5-dihydro-1,2,4-oxadiazoles. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.127820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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2
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Pisani L, Rullo M, Catto M, de Candia M, Carrieri A, Cellamare S, Altomare CD. Structure-property relationship study of the HPLC enantioselective retention of neuroprotective 7-[(1-alkylpiperidin-3-yl)methoxy]coumarin derivatives on an amylose-based chiral stationary phase. J Sep Sci 2018; 41:1376-1384. [DOI: 10.1002/jssc.201701442] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/29/2018] [Accepted: 01/29/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Leonardo Pisani
- Department of Pharmacy-Drug Sciences; University of Bari Aldo Moro; Bari Italy
| | - Mariagrazia Rullo
- Department of Pharmacy-Drug Sciences; University of Bari Aldo Moro; Bari Italy
| | - Marco Catto
- Department of Pharmacy-Drug Sciences; University of Bari Aldo Moro; Bari Italy
| | - Modesto de Candia
- Department of Pharmacy-Drug Sciences; University of Bari Aldo Moro; Bari Italy
| | - Antonio Carrieri
- Department of Pharmacy-Drug Sciences; University of Bari Aldo Moro; Bari Italy
| | - Saverio Cellamare
- Department of Pharmacy-Drug Sciences; University of Bari Aldo Moro; Bari Italy
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3
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Dynamic Behavior of Clobazam on High-Performance Liquid Chromatography Chiral Stationary Phases. Chirality 2015; 28:17-21. [DOI: 10.1002/chir.22542] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/03/2015] [Accepted: 09/09/2015] [Indexed: 12/24/2022]
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4
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Sievers-Engler A, Lindner W, Lämmerhofer M. Ligand–receptor binding increments in enantioselective liquid chromatography. J Chromatogr A 2014; 1363:79-88. [DOI: 10.1016/j.chroma.2014.04.077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/15/2014] [Accepted: 04/20/2014] [Indexed: 10/25/2022]
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5
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Khosrokhavar R, Ghasemi JB, Shiri F. 2D Quantitative structure-property relationship study of mycotoxins by multiple linear regression and support vector machine. Int J Mol Sci 2010; 11:3052-68. [PMID: 20957079 PMCID: PMC2956080 DOI: 10.3390/ijms11093052] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 08/15/2010] [Accepted: 08/16/2010] [Indexed: 11/28/2022] Open
Abstract
In the present work, support vector machines (SVMs) and multiple linear regression (MLR) techniques were used for quantitative structure–property relationship (QSPR) studies of retention time (tR) in standardized liquid chromatography–UV–mass spectrometry of 67 mycotoxins (aflatoxins, trichothecenes, roquefortines and ochratoxins) based on molecular descriptors calculated from the optimized 3D structures. By applying missing value, zero and multicollinearity tests with a cutoff value of 0.95, and genetic algorithm method of variable selection, the most relevant descriptors were selected to build QSPR models. MLR and SVMs methods were employed to build QSPR models. The robustness of the QSPR models was characterized by the statistical validation and applicability domain (AD). The prediction results from the MLR and SVM models are in good agreement with the experimental values. The correlation and predictability measure by r2 and q2 are 0.931 and 0.932, repectively, for SVM and 0.923 and 0.915, respectively, for MLR. The applicability domain of the model was investigated using William’s plot. The effects of different descriptors on the retention times are described.
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Affiliation(s)
- Roya Khosrokhavar
- Food and Drug Laboratory Research Center, MOH & ME, Tehran, Iran; E-Mail:
| | - Jahan Bakhsh Ghasemi
- Department of Chemistry, Faculty of Sciences, K.N., Toosi University of Technology, Tehran 16617, Iran
- * Author to whom correspondence should be addressed; E-Mail: ; Tel.: +98-21-228-502-66; Fax: +98-21-228-536-50
| | - Fereshteh Shiri
- Faculty of Chemistry, Razi University, Kermanshah, Iran; E-Mail:
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Lämmerhofer M. Chiral recognition by enantioselective liquid chromatography: mechanisms and modern chiral stationary phases. J Chromatogr A 2009; 1217:814-56. [PMID: 19906381 DOI: 10.1016/j.chroma.2009.10.022] [Citation(s) in RCA: 505] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/30/2009] [Accepted: 10/07/2009] [Indexed: 11/19/2022]
Abstract
An overview of the state-of-the-art in LC enantiomer separation is presented. This tutorial review is mainly focused on mechanisms of chiral recognition and enantiomer distinction of popular chiral selectors and corresponding chiral stationary phases including discussions of thermodynamics, additivity principle of binding increments, site-selective thermodynamics, extrathermodynamic approaches, methods employed for the investigation of dominating intermolecular interactions and complex structures such as spectroscopic methods (IR, NMR), X-ray diffraction and computational methods. Modern chiral stationary phases are discussed with particular focus on those that are commercially available and broadly used. It is attempted to provide the reader with vivid images of molecular recognition mechanisms of selected chiral selector-selectand pairs on basis of solid-state X-ray crystal structures and simulated computer models, respectively. Such snapshot images illustrated in this communication unfortunately cannot account for the molecular dynamics of the real world, but are supposed to be helpful for the understanding. The exploding number of papers about applications of various chiral stationary phases in numerous fields of enantiomer separations is not covered systematically.
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Affiliation(s)
- Michael Lämmerhofer
- Christian Doppler Laboratory for Molecular Recognition Materials, Department of Analytical Chemistry and Food Chemistry, University of Vienna, Waehringer Strasse 38, A-1090 Vienna, Austria.
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7
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Del Rio A. Exploring enantioselective molecular recognition mechanisms with chemoinformatic techniques. J Sep Sci 2009; 32:1566-84. [DOI: 10.1002/jssc.200800693] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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8
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Ghasemi J, Asadpour S, Abdolmaleki A. Prediction of gas chromatography/electron capture detector retention times of chlorinated pesticides, herbicides, and organohalides by multivariate chemometrics methods. Anal Chim Acta 2007; 588:200-6. [PMID: 17386811 DOI: 10.1016/j.aca.2007.02.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Revised: 02/09/2007] [Accepted: 02/14/2007] [Indexed: 11/29/2022]
Abstract
A quantitative structure-retention relationship (QSRR) study, has been carried out on the gas chromatograph/electron capture detector (GC/ECD) system retention times (t(R)s) of 38 diverse chlorinated pesticides, herbicides, and organohalides by using molecular structural descriptors. Modeling of retention times of these compounds as a function of the theoretically derived descriptors was established by multiple linear regression (MLR) and partial least squares (PLS) regression. The stepwise regression using SPSS was used for the selection of the variables that resulted in the best-fitted models. Appropriate models with low standard errors and high correlation coefficients were obtained. Three types of molecular descriptors including electronic, steric and thermodynamic were used to develop a quantitative relationship between the retention times and structural properties. MLR and PLS analysis has been carried out to derive the best QSRR models. After variables selection, MLR and PLS methods used with leave-one-out cross validation for building the regression models. The predictive quality of the QSRR models were tested for an external prediction set of 12 compounds randomly chosen from 38 compounds. The PLS regression method was used to model the structure-retention relationships, more accurately. However, the results surprisingly showed more or less the same quality for MLR and PLS modeling according to squared regression coefficients R2 which were 0.951 and 0.948 for MLR and PLS, respectively.
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Affiliation(s)
- Jahanbakhsh Ghasemi
- Chemistry Department, Faculty of Sciences, Razi University, Kermanshah, Iran.
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9
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Héberger K. Quantitative structure-(chromatographic) retention relationships. J Chromatogr A 2007; 1158:273-305. [PMID: 17499256 DOI: 10.1016/j.chroma.2007.03.108] [Citation(s) in RCA: 268] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 03/13/2007] [Accepted: 03/19/2007] [Indexed: 01/30/2023]
Abstract
Since the pioneering works of Kaliszan (R. Kaliszan, Quantitative Structure-Chromatographic Retention Relationships, Wiley, New York, 1987; and R. Kaliszan, Structure and Retention in Chromatography. A Chemometric Approach, Harwood Academic, Amsterdam, 1997) no comprehensive summary is available in the field. Present review covers the period of 1996-August 2006. The sources are grouped according to the special properties of kinds of chromatography: Quantitative structure-retention relationship in gas chromatography, in planar chromatography, in column liquid chromatography, in micellar liquid chromatography, affinity chromatography and quantitative structure enantioselective retention relationships. General tendencies, misleading practice and conclusions, validation of the models, suggestions for future works are summarized for each sub-field. Some straightforward applications are emphasized but standard ones. The sources and the model compounds, descriptors, predicted retention data, modeling methods and indicators of their performance, validation of models, and stationary phases are collected in the tables. Some important conclusions are: Not all physicochemical descriptors correlate with the retention data strongly; the heat of formation is not related to the chromatographic retention. It is not appropriate to give the errors of Kovats indices in percentages. The apparently low values (1-3%) can disorient the reviewers and readers. Contemporary mean interlaboratory reproducibility of Kovats indices are about 5-10 i.u. for standard non polar phases and 10-25 i.u. for standard polar phases. The predictive performance of QSRR models deteriorates as the polarity of GC stationary phase increases. The correlation coefficient alone is not a particularly good indicator for the model performance. Residuals are more useful than plots of measured and calculated values. There is no need to give the retention data in a form of an equation if the numbers of compounds are small. The domain of model applicability of models should be given in all cases.
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Affiliation(s)
- Károly Héberger
- Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, H-1525 Budapest, Hungary.
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10
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Yu J, Zhang S, Li Z, Lu W, Zhang L, Zhou R, Liu Y, Cai M. SYNTHESIS, X-RAY DIFFRACTION, AND NMR ANALYSIS OF (2S, 3a′R, 6′S, 7a′R)-3-ACETYL-2′, 2′, 2″, 2″-TETRAMETHYL-5-PHENYL-2, 3-DIHYDRO-1, 3, 4-OXADIAZOLE-2-SPIRO-7′-{1′, 3′-DIOXOLANO [4, 5-c] PYRANO}-6′-SPIRO-4″-(1″, 3″-DIOXOLANE). J Carbohydr Chem 2006. [DOI: 10.1081/car-100108664] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Jianxin Yu
- a National Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Beijing Medical University , Beijing, 100083, China
- b Department of Chemistry , Xinjiang University , Wulumqi, 830046, China
| | - Suna Zhang
- b Department of Chemistry , Xinjiang University , Wulumqi, 830046, China
| | - Zhongjun Li
- a National Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Beijing Medical University , Beijing, 100083, China
| | - Wenjie Lu
- c Department of Chemistry , Wuyi University , Jiangmen, 529020, China
| | - Lijing Zhang
- b Department of Chemistry , Xinjiang University , Wulumqi, 830046, China
| | - Rong Zhou
- b Department of Chemistry , Xinjiang University , Wulumqi, 830046, China
| | - Yuting Liu
- b Department of Chemistry , Xinjiang University , Wulumqi, 830046, China
| | - Mengshen Cai
- a National Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Beijing Medical University , Beijing, 100083, China
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11
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Lämmerhofer M, Franco P, Lindner W. Quinine carbamate chiral stationary phases: Systematic optimization of steric selector-selectand binding increments and enantioselectivity by quantitative structure-enantioselectivity relationship studies. J Sep Sci 2006; 29:1486-96. [PMID: 16894794 DOI: 10.1002/jssc.200600111] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A series of quinine carbamate-based chiral stationary phases (CSPs) differing solely in the carbamate residue have been devised and a congeneric set of N-3,5-dinitrobenzoyl (DNB) amino acids (AAs) was separated into enantiomers on these CSPs by HPLC using a buffered hydro-organic mobile phase. Some details on retention and chiral recognition mechanisms have been investigated by application of quantitative structure-property relationship (QSPR) studies using the linear free energy relationship methodology, i.e., the extrathermodynamic approach. Retention factors of the high affinity enantiomer (log k2) and enantioselectivities (log alpha) were correlated with Taft's steric parameter as structural descriptor for the variability in the carbamate and AA residues, and statistically significant QSPR models could be obtained. They confirmed that the variance in the dependent variable (log k2, log alpha) is mainly associated with the steric bulkiness of the selectors' carbamate and of the AA residues. The retention factor of the second eluted enantiomers and the enantioselectivity first increased with steric bulkiness of the carbamate and AA residues, which may be explained by stronger dispersive interactions. After reaching an optimum, the dependent variable, however, declined with further increase of the steric bulkiness of the substituents, probably because of steric hindrance. The variability of the retention factors of the first eluted enantiomer could not be explained by steric descriptors. Instead, it has become obvious that the retention arises mainly from interactions of the DNB-AA and the quinine carbamate backbone, as it turned out to be more or less constant and solely to a minute amount modulated by the carbamate residue and the AA side chain. The QSPR models were fully in agreement with an earlier postulated chromatographically and spectroscopically derived hypothetical selector-selectand binding model.
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Affiliation(s)
- Michael Lämmerhofer
- Christian Doppler Laboratory for Molecular Recognition Materials, Department of Analytical Chemistry, University of Vienna, Vienna, Austria.
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12
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Kaliková K, Lokajová J, Tesafová E. Linear free energy relationship as a tool for characterization of three teicoplanin-based chiral stationary phases under various mobile phase compositions. J Sep Sci 2006; 29:1476-85. [PMID: 16894793 DOI: 10.1002/jssc.200600017] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Teicoplanin, teicoplanin aglycon, and methylated teicoplanin aglycon chiral stationary phases (CSPs) have been compared on the basis of the regression coefficients calculated from the linear free energy relationship (LFER) equation. The parameters have been obtained from the measurements of a set of 34 structurally diverse solutes. Influence of mobile phase composition - variation of methanol (MeOH) content - on the participation of different interactions types in the retention mechanism has been evaluated. Retention of the various interaction forces in analytes differs with both the CSP and the mobile phase composition. Hydrophobic interactions play a major role in mobile phases for high buffer contents. The more hydrophobic the CSP, the more important are they in the retention mechanism. With increase of MeOH contents in the mobile phase the major role in the interaction mechanism is shifted to more polar forces in which basicity and dipolarity/polarizability dominate. Although the LFER model does not address chiral aspects, we have attempted to explore the importance of the individual interactions in chiral discrimination of amino acids and their N-tert-butyloxycarbonyl derivatives.
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Affiliation(s)
- Kveta Kaliková
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University of Prague, Prague, Czech Republic
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13
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Carcinogenicity of benzo[a]pyrene diol epoxide stereoisomers: A linear free energy relationship study. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.theochem.2006.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Ali I, Kumerer K, Aboul-Enein HY. Mechanistic Principles in Chiral Separations Using Liquid Chromatography and Capillary Electrophoresis. Chromatographia 2006. [DOI: 10.1365/s10337-006-0762-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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15
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Cancelliere G, D'Acquarica I, Gasparrini F, Maggini M, Misiti D, Villani C. Twenty years of research on silica-based chiral stationary phases. J Sep Sci 2006; 29:770-81. [PMID: 16830489 DOI: 10.1002/jssc.200500517] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This review provides an overview of twenty years of pioneering work (from 1985 to 2005) of our research group in the preparation and application of enantioselective packing materials for HPLC. After a brief introduction to the rational design of a new chiral stationary phase, a detailed presentation in chronological order of appearance in the literature is given of the currently developed repertoire of chiral stationary phases and their typical applications. Emphasis is placed on the different synthetic strategies exploited to obtain highly efficient, stable, and versatile chiral stationary phases.
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Affiliation(s)
- Giovanna Cancelliere
- Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Università "La Sapienza", Roma, Italy
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16
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Zhong Q, Han X, He L, Beesley TE, Trahanovsky WS, Armstrong DW. Chromatographic evaluation of poly (trans-1,2-cyclohexanediyl-bis acrylamide) as a chiral stationary phase for HPLC. J Chromatogr A 2005; 1066:55-70. [PMID: 15794555 DOI: 10.1016/j.chroma.2004.12.088] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chiral stationary phases (CSPs) based on polymeric (R,R)- or (S,S)-1,2-diaminocyclohexane (DACH) derivatives are synthesized. When bonded to 5 microm porous spherical silica gel, the poly (trans-1,2-cyclohexanediyl-bis acrylamide) based poly-cyclic amine polymer (P-CAP) stationary phases is proved to be effective chiral stationary phases that could be used in the normal-phase mode, polar organic mode and with halogenated solvents mobile phases, if desired. Since these are entirely synthetic CSPs, the elution order of all enantiomers can be reversed between the (R,R) P-CAP and (S,S) P-CAP columns. Because of the high loading of chiral selectors, the columns exhibit very high sample capacities. Thus, P-CAP columns are useful for preparative and semi-preparative enantiomeric separations. The application of these CSPs and optimization of their separations are discussed.
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Affiliation(s)
- Qiqing Zhong
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA
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17
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Yu J, Zhang S, Li Z, Lu W, Cai M. Stereoselective synthesis, structural characterization, and properties of 1,2-O-isopropylidene-3-C-(5-phenyl-1,2,4-oxadiazol-3-yl)-β-d-psicopyranose. Bioorg Med Chem 2005; 13:353-61. [PMID: 15598558 DOI: 10.1016/j.bmc.2004.10.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2003] [Revised: 10/07/2004] [Accepted: 10/09/2004] [Indexed: 11/19/2022]
Abstract
1,2:4,5-Di-O-isopropylidene-3-C-(5-phenyl-1,2,4-oxadiazol-3-yl)-beta-D-psicopyranose 14 was synthesized stereoselectively from 1,2:4,5-di-O-isopropylidene-3-C-amidoximino-3-O-benzoyl-beta-D-psicopyranose 8 using a novel procedure. Treatment of 8 with acetic anhydride, chloroacetyl chloride, propanic anhydride, or benzoyl chloride causes the 3-O-benzoyl group to undergo an intramolecular replacement reaction with neighboring group participation and transfer resulting in a more stable conjugation system of the 1,2,4-oxadiazol ring. A possible mechanism, as well as structural analysis and bioactivity are described.
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Affiliation(s)
- Jianxin Yu
- Advanced Radiological Sciences, Department of Radiology, The University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, TX 75390-9058, USA.
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18
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Srivastava RM, de Freitas Filho JR, da Silva MJ, de Melo Souto SC, Carpenter GB, Faustino W. Synthesis, separation and configuration determination of diastereoisomers of (R,S)-1-methyl-3-[3-(aryl)-1,2,4-oxadiazol-5-yl] propyl 2,3-dideoxy-α-d-erythro-hex-2-enopyranosides. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.08.075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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19
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Fabian WMF, Stampfer W, Mazur M, Uray G. Modeling the chromatographic enantioseparation of aryl- and hetarylcarbinols on ULMO, a brush-type chiral stationary phase, by 3D-QSAR techniques. Chirality 2003; 15:271-5. [PMID: 12582994 DOI: 10.1002/chir.10197] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The enantiomers of a series of chiral aryl- and hetaryl-carbinols were separated on a chiral stationary phase (ULMO) based on (S,S)-3,5-dinitrobenzoylated 1,2-diphenylethane-1,2-diamine. In all cases, the homochiral analogs of (S)-1-phenylethanol (mostly also S-enantiomers) were retained more. Log alpha values were modeled with the aid of the 3D-QSAR techniques CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indices analysis) as well as a descriptor based on normal mode eigenvalues (EVA). Partial least-squares analysis with two (CoMSIA) or three (CoMFA, EVA) latent variables on a set of 22 training analytes gives cross-validated correlation coefficients q(2) = 0.85-0.91 and conventional correlation coefficients r(2) = 0.94-0.99. The quantitative structure-enantioselective retention relationships derived thereby were used to predict the separation factors of the test set, containing also hetaryl-carbinols, e.g., furan and thiophene analogs, with good accuracy.
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Yu J, Zhang S, Li Z, Lu W, Zhou R, Liu Y, Cai M. Stereoselective synthesis of 1,2:4,5-di-O-isopropylidene-3-C-(5-phenyl-1,2,4-oxadiazol-3-yl)-beta-D-psicopyranose and its X-ray crystallographic analysis. Carbohydr Res 2003; 338:257-61. [PMID: 12543558 DOI: 10.1016/s0008-6215(02)00401-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In a novel procedure, when 3-O-benzoyl-3-C-(N-hydroxycarbamimidoyl)-1,2:4,5-di-O-isopropylidene-beta-D-psicopyranose (1) is treated with acetic anhydride, chloroacetyl chloride, propanic anhydride and benzoyl chloride, the 3-O-benzoyl group undergoes an intramolecular replacement reaction with neighbouring group participation and transfer resulting in a more stable conjugated system by the formation of a 1,2,4-oxadiazol ring. A possible mechanism is reported. The structure has been determined by spectroscopic data and X-ray crystallographic analysis.
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Affiliation(s)
- Jianxin Yu
- Department of Chemistry, Xinjiang University, Wulumqi 830046, China.
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21
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Suzuki T, Timofei S, Iuoras BE, Uray G, Verdino P, Fabian WM. Quantitative structure-enantioselective retention relationships for chromatographic separation of arylalkylcarbinols on Pirkle type chiral stationary phases. J Chromatogr A 2001; 922:13-23. [PMID: 11486858 DOI: 10.1016/s0021-9673(01)00921-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Quantitative structure-retention (QSRR, retention factors log k1 and log k2 for the first and second eluted enantiomer) as well as enantioselective retention relationships (QSERR, separation factor log a) for a series of 42 chiral arylalkylcarbinols on four brush-type chiral stationary phases are derived by multiple linear regression analyses and artificial neuronal network calculations using 2D and 3D molecular descriptors including those obtained by quantum chemical calculations. Separation factors are in addition modeled by the 3D-QSAR method of comparative molecular field analysis (CoMFA). For the retention factors the LUMO energy turns out to be the most important descriptor, whereas for log a it is the hydrophobicity of the analytes. With CoMFA both the steric and electrostatic field are found to be of almost comparable significance.
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Affiliation(s)
- T Suzuki
- Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama, Japan
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22
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Savini L, Chiasserini L, Pellerano C, Biggio G, Maciocco E, Serra M, Cinone N, Carrieri A, Altomare C, Carotti A. High affinity central benzodiazepine receptor ligands. Part 2: quantitative structure-activity relationships and comparative molecular field analysis of pyrazolo[4,3-c]quinolin-3-ones. Bioorg Med Chem 2001; 9:431-44. [PMID: 11249135 DOI: 10.1016/s0968-0896(00)00262-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A large series of 2-aryl(heteroaryl)-2,5-dihydropyrazolo[4,3-c]quinolin-3(3H)-ones (PQ, 106 compounds), carrying appropriate substituents at the quinoline and N2-phenyl rings, were designed, prepared and tested as central benzodiazepine receptor ligands. Compounds with an affinity significantly higher than the parent compound CGS-8216 were obtained, the most active ligand showing a pIC50 = 10.35. Hansch and comparative molecular field analyses gave coherent results suggesting the main structural requirements of high receptor binding affinity. The possible formation of a three-centred hydrogen bond (HB) at the HB donor site H2, as a key interaction for high receptor binding affinity, was assessed by the calculation and comparison of the molecular electrostatic potentials of a series of selected ligands.
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Affiliation(s)
- L Savini
- Dipartimento Farmaco Chimico, Università degli Studi, Bari, Italy
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23
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Schefzick S, Lämmerhofer M, Lindner W, Lipkowitz KB, Jalaie M. Comparative molecular field analysis of quinine derivatives used as chiral selectors in liquid chromatography: 3D QSAR for the purposes of molecular design of chiral stationary phases. Chirality 2000; 12:742-50. [PMID: 11054833 DOI: 10.1002/1520-636x(2000)12:10<742::aid-chir7>3.0.co;2-m] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A comparative molecular field analysis (CoMFA) was carried out on a set of aligned quinine-based stationary phase molecules used in enantioselective chromatography. The best QSAR derived has a cross-validated (predictive) r(2)(cv) = 0.671 and a normal r(2) = 0.998. For CoMFAs using both steric and electrostatic fields as descriptors, the steric field descriptors explained more than 91% of the variance while the electrostatic descriptors explained less than 9% of the variance. It is concluded that the long-range electrostatic potential surrounding the positively charged CSPs are not enantiodiscriminating, while the van der Waals and local electrostatic surface features of these CSPs are highly discriminating. Quantum mechanical calculations back up this claim by showing a relatively symmetric electrostatic iso-contour surface. From the QSAR derived here, a region around the carbamate moiety was located where placement of steric bulk is predicted to enhance chiral discrimination. A set of possible synthetic target molecules is presented.
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Affiliation(s)
- S Schefzick
- Department of Analytical Chemistry, University of Vienna, Vienna, Austria
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24
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Chapter 9 Recent developments in liquid chromatographic enantioseparation. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1567-7192(00)80012-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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25
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Cancelliere G, D'Acquarica I, Gasparrini F, Misiti D, Villani C. Synthesis and applications of novel, highly efficient HPLC chiral stationary phases: a chiral dimension in drug research analysis. PHARMACEUTICAL SCIENCE & TECHNOLOGY TODAY 1999; 2:484-492. [PMID: 10603466 DOI: 10.1016/s1461-5347(99)00218-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This review provides an overview of the synthesis and application of stable and versatile HPLC chiral stationary phases (CSPs), with emphasis placed on the binding strategies developed to anchor several structurally different chiral selectors to silica-gel microparticles. In addition, selected applications relating to the use of these CSPs for the direct resolution of racemates of biological and pharmaceutical relevance will be described. This review discusses enantioselective molecular recognition and dynamic stereochemistry of stereolabile compounds with reference to receptor-based chiral stationary phases (CSPs) and dynamic HPLC on CSPs, respectively.
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Affiliation(s)
- G Cancelliere
- Dipartimento di Studi di Chimica, e Tecnologia delle Sostanze, Biologicamente Attive, Università La Sapienza, P.le A. Moro 5, I-00185 Rome, Italy
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26
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Carotti A, Di Gioia F, Cellamare S, Fanali S. Teicoplanin-Based Enantiomeric Separations in CZE Using a Partial Filling Technique. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1521-4168(19990601)22:6<315::aid-jhrc315>3.0.co;2-n] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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27
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Zhang M, Zhang H, Yang Z, Ma L, Min J, Zhang L. Synthesis of 3-C-(methyl beta-D-xylofuranosid-3-yl)-5-phenyl-1,2,4-oxadiazole. Carbohydr Res 1999; 318:157-61. [PMID: 10515054 DOI: 10.1016/s0008-6215(99)00106-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nucleophilic addition of KCN to 5-O-benzoyl-1,2-O-isopropylidene-alpha-D-erythro-pentofuranos-3-++ +ulose gave the xylo cyanohydrin stereoselectively. Several xylos-3-yl-1,2,4-oxadiazole derivatives were synthesized from this cyanohydrin and were converted into 3-C-(methyl beta-D-xylofuranosid-3-yl)-5-phenyl-1,2,4-oxadiazole.
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Affiliation(s)
- M Zhang
- National Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Beijing Medical University, People's Republic of China
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