Download or read book Modified Cyclodextrins for Chiral Separation written by Weihua Tang and published by Springer Science & Business Media. This book was released on 2013-05-24 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modified Cyclodextrins for Chiral Separation offers a review of the latest advances in developing modified cyclodextrins as chiral selectors for various chromatographic and electromigration techniques. Over the years, many descriptions of chiral separation have appeared in academic journals and books, but most of them have been devoted to either the development of analytical methods and protocols or the summary of different chiral selectors, including cyclodextrins for chiral separation applications. This is in marked contrast to this volume which focuses on the research endeavors concerning the development of cyclodextrin derivatives specifically as either chiral mobile phases for capillary electrophoresis, or chiral stationary phases for various chromatographic techniques including gas chromatography, or high-performance liquid chromatography and supercritical fluid chromatography. The ongoing thread in this book is the synthesis of structurally-defined cyclodextrin derivatives and their applications in enantiomer separation by means of different analytical techniques. Modified Cyclodextrins for Chiral Separation is intended for those who are interested in expanding their knowledge of cyclodextrin chemistry and chiral separation, and in what cyclodextrin modification can be made to suit the needs of chiral selectors for different analytical techniques. It primarily focuses on the state-of-the-art cyclodextrin chemistry which is the basis for all chiral selectors used in these chiral separation techniques. Weihua Tang, PhD, is a professor at the Key Laboratory of Soft Chemistry and Functional Materials, Ministry of Education, Nanjing University of Science and Technology, China. Siu-Choon Ng, PhD, is a professor at the Division of Chemical and Biomedical Engineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore. Dongping Sun, PhD, is a professor at the Key Laboratory of Soft Chemistry and Functional Materials, Ministry of Education, Nanjing University of Science and Technology, China.
Download or read book Modified Cyclodextrins as Chiral Stationary Phases for Capillary Gas Chromatographic Separation of Enantiomers written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclodextrin (CD) derivatives are widely used as chiral stationary phases in capillary gas chromatography. Their performance depends substantially on the side chains attached to the hydroxyl groups of the glucose moieties. In this study new classes of CD-derivatives suitable for gas chromatographic (GC) separation of enantiomers were synthesized by introducing (i) acetal functions and (ii) chiral acyl moieties at positions 2 and 3 of the glucose units. Octakis(2,3-di-O-methoxymethyl-6-O-tert-butyldimethylsilyl)-g-cyclodextrin (2,3- MOM-6-TBDMS-g-CD) obtained by reaction of 6-O-TBDMS-g-cyclodextrin with methoxymethylchloride (MOM-Cl) was synthesized as first representative of cyclodextrin GC stationary phases containing alkoxymethyl side chains. The structure was confirmed by NMR and mass spectrometry. The suitability of the material diluted in polysiloxane as GC stationary phase was shown. Enantioseparations could be achieved for a broad spectrum of chiral volatiles from various chemical classes. Structural influences of the analytes on the enantiodifferentiations were demonstrated. High separation factors were observed for the hydroxyketone acetoin (a = 1.8) and some methyl branched ketones. Pronounced enantioseparations were also determined for cyclic pentenolone and furanone derivatives. To investigate the impact of the size of the CD torus, the 2,3-MOM-derivatives of the b- and a-CD analogs were synthesized. The spectrum of compounds for which enantiomers could be separated on 2,3-MOM-6-TBDMS-b-CD was more limited and the enantioseparations achieved were generally less pronounced compared to the g-CD derivative. However, for 2-alkyl esters unusually high separation factors (a up to 4.31) were observed. Using 2-pentyl acetate as example, phenomena underlying the enantioseparation were investigated by determining thermodynamic parameters. The data showed that only one enantiomer is retained significantly on the chiral stationary phase whereas the other one behaves.
Download or read book Modified Cyclodextrins as Chiral Stationary Phases for Capillary Gas Chromatographic Separation of Enantiomers written by Eisuke Takahisa and published by . This book was released on 2005 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gas Chromatographic Enantiomer Separation with Modified Cyclodextrins written by Wilfried A. König and published by . This book was released on 1992 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Preparation of Novel Modified Cyclodextrins and Their Application in Enantioseparations by Gas Chromatography written by Sheree N. Allen and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Since biological processes depend on the stereospecific creation and conversion of chiral molecules, each enantiomer of a molecule can have a different biological effect. While numerous synthetic drugs are sold in racemic form for reasons of cost and convenience, in many cases one of the two enantiomers of a drug will cause undesirable and perhaps even devastating effects. Therefore, effective methods for the separation and quantification of enantiomers are of great importance. Enantiomers can be separated only with the use of systems containing an optically active chiral selector. Modified cyclodextrins (CDs) are widely used as chiral selectors by virtue of their ability to form inclusion complexes. Because of the remarkably high efficiency, and sensitivity of chiral gas chromatography (GC), chiral separations by this method represent a preferred method for enantiomer analysis. The basic property of CDs that allows them to be successful for enantiomer separations is their ability to form selective inclusion complexes with a wide variety of organic molecules. The preparation and application of modified cyclodextrins for the GC separation of enantiomers is a focal point of this research. In effort to identify useful new derivatives, modifications involving unique and separate reaction of the secondary hydroxyl groups and/or annulations bridging the secondary oxygens have been examined. Several new cyclodextrin derivatives, e.g. per(6-OTBS-2,3-O-diformyl)-[beta]-CD, per(6-OTBS-2,3-O-cyclodimethylsilyl)-[beta]-CD, per(6-deoxy-2,3-O-cyclodimethylsilyl)-[beta]-CD and a mixed formyl/acetyl phase have been synthesized and evaluated as components of stationary phases for capillary GC. The efficiency of each new phase to separate enantiomers was evaluated against a 30 analyte panel to evaluate the influence of the different substituents on the selectivity. These enantioseparations were also compared to those observed on four commercially available chiral phases using the same 30 analyte panel. Overall, this work resulted in nine new CD derivatives and the discovery of a new chiral selector that is comparable in efficiency to what is currently commercially available.
Download or read book Modified Cyclodextrins Scaffolds And Templates For Supramolecular Chemistry written by Chris J Easton and published by World Scientific. This book was released on 1999-04-29 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: Through modification, the natural cyclodextrins are effective templates for the generation of a wide range of molecular hosts. This makes it possible to tailor a cyclodextrin host to a particular guest, to meet specific requirements in the host-guest complex, and opens the way to diverse new areas of supramolecular chemistry. Metallocyclodextrins, rotaxanes and catenanes, as well as surface monolayers of modified cyclodextrins, are readily obtained. The native cyclodextrins serve as scaffolds on which functional groups and other substituents can be assembled, with controlled geometry. This results in substantially improved molecular recognition and procedures for chemical separation, including enantiomer discrimination, through guest binding. Access to the gamut of functional groups greatly expands the utility of cyclodextrins in chemical synthesis and provides catalysts which mimic the entire range of enzymic activity. Modifications to the cyclodextrins also lead to a wide range of photochemistry of cyclodextrin complexes, through which the enhancement of guest reactivity occurs; in addition, light harvesting molecular devices and photochemical frequency switches may be constructed. In solution, modified cyclodextrins have been used to construct molecular reactors, as well as molecular, temperature and pH sensors. At surfaces, they form semipermeable membranes and sensor electrodes. Such exciting fields of chemistry, made possible only through modifications to the natural cyclodextrins, are the subject of this book.
Download or read book Modified Cyclodextrins written by Christopher J. Easton and published by Imperial College Press. This book was released on 1999-01-01 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Through modification, the natural cyclodextrins are effective templates for the generation of a wide range of molecular hosts. This makes it possible to tailor a cyclodextrin host to a particular guest, to meet specific requirements in the host -- guest complex, and opens the way to diverse new areas of supramolecular chemistry. Metallocyclodextrins, rotaxanes and catenanes, as well as surface monolayers of modified cyclodextrins, are readily obtained. The native cyclodextrins serve as scaffolds on which functional groups and other substituents can be assembled, with controlled geometry. This results in substantially improved molecular recognition and procedures for chemical separation, including enantiomer discrimination, through guest binding. Access to the gamut of functional groups greatly expands the utility of cyclodextrins in chemical synthesis and provides catalysts which mimic the entire range of enzymic activity. Modifications to the cyclodextrins also lead to a wide range of photochemistry of cyclodextrin complexes, through which the enhancement of guest reactivity occurs; in addition, light harvesting molecular devices and photochemical frequency switches may be constructed. In solution, modified cyclodextrins have been used to construct molecular reactors, as well as molecular, temperature and pH sensors. At surfaces, they form semipermeable membranes and sensor electrodes. Such exciting fields of chemistry, made possible only through modifications to the natural cyclodextrins, are the subject of this book.
Download or read book Design and Synthesis of Novel beta cyclodextrins and Their Application as Chiral Stationary Phases for Gas Chromatography written by Tiffany R. Turner Hayden and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Enantiomers can be directly separated only with use of systems containing a chiral selector. Cyclodextrins (CDs) and modified cyclodextrins have been used as chiral selectors for their ability to form host-guest complexes with various analytes. The scaffold of the CD allows for assembly of functional groups with controlled geometry. CDs can be readily modified through substitution of the hydroxyl groups, giving rise to derivatives with significantly different properties, especially increased solubility and controlling the hydrophobicity of the cavity. Even though CDs can be readily modified, the syntheses can be tedious and complicated with various protecting group strategies to control the reactivity of the various alcohols. The preparation of modified cyclodextrins for use as chiral stationary phases (CSP) for gas chromatography (GC) is the focal point of this research. Our effort to identify useful new [beta]-CD derivatives involved attempts to make bridged (annulated) derivatives, could increase the thermal stability of the derivatives, and change the length, width and polarity of the CD cavity. To date, there are no reports of annulated CD derivatives in the chemical literature. In the process of evaluating a wide range of electrophiles that could accomplish annulation, several new [beta]-CD derivatives, i.e., per(6-O-TBS-2,3-O-cyclodimethylsilyl)- [beta]-CD, per(6-O-TBS-2,3-O-cyclodiphenylsilyl)- [beta]-CD, per(6-O-Pivaloyl-2,3-O-cyclodimethylsilyl)-[beta]-CD, per(6-deoxy-2,3-O-methyl)- [beta]-CD, and per(6-deoxy-2,3-O-allyl)- [beta]-CD, were synthesized. Two of the new derivatives were evaluated as components of stationary phases for GC, per(6-O-TBS-2,3-Ocyclodimethylsilyl)-[beta]-CD and per(6-deoxy-2,3-O-methyl)-[beta]-CD. Overall, this work resulted in five new CD derivatives.
Download or read book Gas Chromatographic Enantiomer Separation of Atropisomeric PCBs Using Modified Cyclodextrins as Chiral Phases written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cyclodextrins in Chromatography written by Tibor Cserháti and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclodextrins can form complexes with a wide variety of organic and inorganic compounds, a property which can prove useful when trying to separate complex mixtures. This book provides an up-to-date and critical evaluation of the application of cyclodextrins in many fields of chromatography (including thin layer, gas-liquid, high performance liquid and supercritical fluid chromatography; capillary electrophoresis; and isotacophoresis). Whilst mainly practical in nature, the book also looks briefly at the theoretical background for the various techniques. Any professional working with chromatography will welcome this unique book as both a practical compilation of methods and a source of reference to the literature regarding the use and impact of cyclodextrins in chromatography.
Download or read book Part 1 Modification of Sulfated beta cyclodextrin Chiral Stationary Phase and Its Application for Chiral Separation in HPLC written by Yingkun Jin and published by . This book was released on 1997 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cyclodextrins Preparation And Application In Industry written by Zhengyu Jin and published by World Scientific. This book was released on 2018-01-10 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclodextrins are an extremely versatile class of chemicals highly prized for their ability to incorporate a plethora of organic, inorganic and biologic guest molecules into their hydrophobic cavities and form host-guest inclusion complexes. As excellent molecular receptors, they have long been exploited in many important industries such as food and agriculture, pharmaceuticals, cosmetics, textiles, analytical chemistry and enzyme mimics.Researchers, technicians and application specialists in many industries will appreciate this handy volume that systematically discusses how cyclodextrins are applied in their industries. Special attention is devoted to the preparation of inclusion complexes, novel properties of the resultant complexes, and details on applying those properties to industry.
Download or read book Chiral Separations and Stereochemical Elucidation written by Quezia Bezerra Cass and published by John Wiley & Sons. This book was released on 2023-03-29 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt: An expert resource for chemists using stereochemical analysis methods In Chiral Separations and Stereochemical Elucidation: Fundamentals, Methods, and Applications, a team of distinguished researchers delivers a robust and authoritative discussion of the theoretical fundamentals of chiral separation, the most commonly used chiral selectors, and stereochemical elucidation methods. The book offers expert discussions of a variety of chiral separation methods by gas chromatography (GC), supercritical fluid chromatography (SFC), capillary electrophoresis (CE), and liquid chromatography (LC). The authors also describe several methods for stereochemical elucidation, including X-ray crystallography, nuclear magnetic resonance spectroscopy, and chiroptical methods. The explored material is ideal for practicing chemists seeking a resource to help them guide method development and optimization or to explain quality control-complements during target compound production. Readers will also find: A thorough introduction to the most important advances and applications in LC, GC, CE, SFC, and preparative chromatography Comprehensive explorations of the role of 2D-LC for chiral separation methods development and applications Practical discussions of the design, mechanisms, and applications of the most commonly used chiral selectors Fulsome treatments of the theoretical backgrounds, advantages, limitations, and applications of stereochemical elucidation methods Perfect for academic and industrial chemists specially in organic, analytical chemistry and pharmaceutical analysis. Chiral Separations and Stereochemical Elucidation: Fundamentals, Methods, and Applications will also benefit biochemists, environmental analysts, forensic and medicinal chemists as well as natural product chemists and those involved with stereochemistry or structural elucidation.
Download or read book Capillary Electrophoresis in Chiral Analysis written by Bezhan Chankvetadze and published by John Wiley & Sons. This book was released on 1997-12-29 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: Das weltweite Interesse an der Trennung von Enantiomeren, Spiegelbildern ein und derselben chemischen Verbindung, nimmt zu, da diese Formen beispielsweise verschiedene physiologische Wirkungen hervorrufen können. Eine hochaktuelle Technik der Stofftrennung in diesem Zusammenhang ist die Kapillarelektrophorese, die hier von den theoretischen Grundlagen bis hin zu analytischen Details und Anbieterlisten ausführlich beschrieben wird.
Download or read book Chiral Separations written by Gerald Gübitz and published by Springer Science & Business Media. This book was released on 2008-02-02 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prominent experts from around the world detail the chromatographic and electroseparation techniques they have developed for chiral separations on an analytical scale. Described in step-by-step detail to ensure successful experimental results, the procedures are presented as either general methods or as specific applications to substance classes and special compounds, with emphasis on high performance liquid chromatography and capillary electrophoresis techniques, but also including thin layer chromotographic, gas chromatographic, supercritical fluid chromatographic as well as recent electrochromotographic techniques.
Download or read book Advances in Chromatography Volume 46 written by Eli Grushka and published by CRC Press. This book was released on 2007-11-05 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by leading international experts in academia and industry, Advances in Chromatography, Volume 46 presents all new chapters with thorough reviews on the latest developments in the field. Volume 46 includes new advances in two-dimensional gas chromatography, reversed phase liquid chromatography/shape selectivity, and supercri
Download or read book Differentiation of Enantiomers I written by Volker Schurig and published by Springer. This book was released on 2013-12-16 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry presents critical reviews of the present and future trends in modern chemical research. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.