Author: Jan J. OltvoortPublisher:
ISBN:
Category :
Languages : en
Pages : 106
Book Description
A Study Directed Towards the Synthesis of Some Naturally Occurring Carbohydrate Derivatives
Author: Jan J. OltvoortA study directed towards the synthesis of some naturally occuring carbohydrate derivatives
Author: Jan J. OltvoortA Study Directed Towards the Synthesis of Some Naturally Occurring Carbohydrate Derivatives
Author: Jan Johannes OltvoortPublisher:
ISBN:
Category :
Languages : en
Pages : 112
Book Description
Studies in Natural Products Chemistry
Author: Atta-ur RahmanPublisher: Elsevier
ISBN: 0323910963
Category : Science
Languages : en
Pages : 452
Book Description
Studies in Natural Products Chemistry, Volume 71 covers the synthesis, testing and recording of the medicinal properties of natural products, providing cutting-edge accounts of the fascinating developments in the isolation, structure elucidation, synthesis, biosynthesis and pharmacology of a diverse array of bioactive natural products. With the rapid developments in spectroscopic techniques and accompanying advances in high-throughput screening techniques, it has become possible to isolate and then determine the structures and biological activity of natural products rapidly, thus opening up exciting opportunities in the field of new drug development to the pharmaceutical industry. Natural products in the plant and animal kingdom offer a huge diversity of chemical structures that are the result of biosynthetic processes that have been modulated over the millennia through genetic effects, hence users will find the detailed information in this book to be a great resource on the topics covered. Focuses on the chemistry of bioactive natural products Contains contributions by leading authorities in the field Presents sources of new pharmacophores
The Organic Chemistry of Sugars
Author: Daniel E. LevyPublisher: CRC Press
ISBN: 1420027956
Category : Medical
Languages : en
Pages : 904
Book Description
Intrigued as much by its complex nature as by its outsider status in traditional organic chemistry, the editors of The Organic Chemistry of Sugars compile a groundbreaking resource in carbohydrate chemistry that illustrates the ease at which sugars can be manipulated in a variety of organic reactions. Each chapter contains numerous examples demonst
Combinatorial Synthesis of Natural Product-Based Libraries
Author: Armen M. BoldiPublisher: CRC Press
ISBN: 1000612015
Category : Science
Languages : en
Pages : 354
Book Description
Traditionally, the search for new compounds from natural products has been a time- and resource-intensive process. The recent application of combinatorial methods and high-throughput synthesis has allowed scientists to generate a range of new molecular structures from natural products and observe how they interact with biological targets. Combinato
Polymers as Aids in Organic Chemistry
Author: N.K MatherPublisher: Elsevier
ISBN: 0323141196
Category : Science
Languages : en
Pages : 271
Book Description
Polymers as Aids in Organic Chemistry covers the broad classifications and application of polymers in organic chemistry. This book is organized into 15 chapters that focus on the transformation of polymers and their role in other reagents that must be easily separated from their final product. After a brief introduction to polymer chemistry, the book presents a tabulation of the various types of polymers that have been used and the methods for their characterization. It then discusses the use of polymers as supports in peptide, oligonucleotide, and oligosaccharide chemistry; in peptide sequencing; in monofunctionalized difunctional compounds preparation, as aids in asymmetric syntheses; and as trapping agents in the determination of reaction intermediates. The subsequent chapters describe the use of polymers as catalysts, with particular emphasis on transition metals immobilized in the polymer matrix and used as catalysts. The concluding chapters examine polymer-immobilized compounds, enzymes, and whole cells that have been used to carry out a large number of reaction, most of which impinge on the area of organic chemistry. Polymer scientists and researchers and organic chemists will find this book invaluable.
Advances in Carbohydrate Chemistry
Author: Publisher: Academic Press
ISBN: 0080562809
Category : Science
Languages : en
Pages : 585
Book Description
Advances in Carbohydrate Chemistry
C-Furanosides
Author: Peter GoekjianPublisher: Academic Press
ISBN: 012803789X
Category : Science
Languages : en
Pages : 796
Book Description
Carbon analogs of carbohydrates, dubbed C-glycosides, have remained an important and interesting class of mimetics, be it in natural product synthesis, for pharmacological applications, as conformational probes, or for biological studies. C-Furanosides: Synthesis and Stereochemistry provides a much-needed overview of synthetic and stereochemical principles for C-furanosides: analogs of a 5-membered ring carbohydrate glycoside (furanoside), in which the anomeric oxygen has been replaced with a carbon. While our understanding of conformational behavior and of stereoselective synthesis in 6-membered ring compounds is quite good, our ability to predict the conformation of 5-membered ring compounds, or to predict the stereochemical outcome of a given reaction, remains anecdotal. Through a comprehensive review of literature approaches to the different C-furanoside stereoisomers, as well as an interpretation of the outcome in terms of a reasonable number of stereochemical models, C-Furanosides: Synthesis and Stereochemistry enables the reader to determine the best approach to a particular C-glycoside compound, and also hopes to provide a certain level of rationalization and predictability for the synthesis of new systems. Provides a comprehensive review of the growing literature in C-furanosides Enables readers to choose the most convenient approach to access a defined target in natural products synthesis or pharmacology and make reasonable predictions for the stereochemical outcome in unpublished cases Explores the various rational models for stereochemical analysis of furanoside reactivity, with a clear distinction made between physical chemical mechanisms and stereochemical models
Asymmetric and Selective Biocatalysis
Author: Jose M. PalomoPublisher: MDPI
ISBN: 3038978469
Category : Science
Languages : en
Pages : 154
Book Description
This Issue contains one communication, six articles, and two reviews. The communication from Paola Vitale et al. represents a work where whole cells were used as biocatalysts for the reduction of optically active chloroalkyl arylketones followed by a chemical cyclization to give the desired heterocycles. Among the various whole cells screened (baker’s yeast, Kluyveromyces marxianus CBS 6556, Saccharomyces cerevisiae CBS 7336, Lactobacillus reuteri DSM 20016), baker’s yeast provided the best yields and the highest enantiomeric ratios (95:5) in the bioreduction of the above ketones. In this respect, valuable chiral non-racemic functionalized oxygen-containing heterocycles (e.g., (S)-styrene oxide, (S)-2-phenyloxetane, (S)-2-phenyltetrahydrofuran), amenable to be further elaborated on, can be smoothly and successfully generated from their prochiral precursors. Studies about pure biocatalysts with mechanistical studies, application in different reactions, and new immobilization methods for improving their stability were reported in five different articles. The article by Su-Yan Wang et al. describes the cloning, expression, purification, and characterization of an N-acetylglucosamine 2-epimerase from Pedobacter heparinus (PhGn2E). For this, several N-acylated glucosamine derivatives were chemically synthesized and used to test the substrate specificity of the enzyme. The mechanism of the enzyme was studied by hydrogen/deuterium NMR. The study at the anomeric hydroxyl group and C-2 position of the substrate in the reaction mixture confirmed the epimerization reaction via ring-opening/enolate formation. Site-directed mutagenesis was also used to confirm the proposed mechanism of this interesting enzyme. The article by Forest H. Andrews et al. studies two enzymes, benzoylformate decarboxylase (BFDC) and pyruvate decarboxylase (PDC), which catalyze the non-oxidative decarboxylation of 2-keto acids with different specificity. BFDC from Pseudomonas putida exhibited very limited activity with pyruvate, whereas the PDCs from S. cerevisiae or from Zymomonas mobilis showed virtually no activity with benzoylformate (phenylglyoxylate). After studies using saturation mutagenesis, the BFDC T377L/A460Y variant was obtained, with 10,000-fold increase in pyruvate/benzoylformate. The change was attributed to an improvement in the Km value for pyruvate and a decrease in the kcat value for benzoylformate. The characterization of the new catalyst was performed, providing context for the observed changes in the specificity. The article by Xin Wang et al. compares two types of biocatalysts to produce D-lysine L-lysine in a cascade process catalyzed by two enzymes: racemase from microorganisms that racemize L-lysine to give D,L-lysine and decarboxylase that can be in cells, permeabilized cells, and the isolated enzyme. The comparison between the different forms demonstrated that the isolated enzyme showed the higher decarboxylase activity. Under optimal conditions, 750.7 mmol/L D-lysine was finally obtained from 1710 mmol/L L-lysine after 1 h of racemization reaction and 0.5 h of decarboxylation reaction. D-lysine yield could reach 48.8% with enantiomeric excess (ee) of 99%. In the article by Rivero and Palomo, lipase from Candida rugosa (CRL) was highly stabilized at alkaline pH in the presence of PEG, which permitted its immobilization for the first time by multipoint covalent attachment on different aldehyde-activated matrices. Different covalent immobilized preparation of the enzyme was successfully obtained. The thermal and solvent stability was highly increased by this treatment, and the novel catalysts showed high regioselectivity in the deprotection of per-O-acetylated nucleosides. The article by Robson Carlos Alnoch et al. describes the protocol and use of a new generation of tailor-made bifunctional supports activated with alkyl groups that allow the immobilization of proteins through the most hydrophobic region of the protein surface and aldehyde groups that allows the covalent immobilization of the previously adsorbed proteins. These supports were especially used in the case of lipase immobilization. The immobilization of a new metagenomic lipase (LipC12) yielded a biocatalyst 3.5-fold more active and 5000-fold more stable than the soluble enzyme. The PEGylated immobilized lipase showed high regioselectivity, producing high yields of the C-3 monodeacetylated product at pH 5.0 and 4 °C. Hybrid catalysts composed of an enzyme and metallic complex are also treated in this Special Issue. The article by Christian Herrero et al. describes the development of the Mn(TpCPP)-Xln10A artificial metalloenzyme, obtained by non-covalent insertion of Mn(III)-meso-tetrakis(p-carboxyphenyl)porphyrin [Mn(TpCPP), 1-Mn] into xylanase 10A from Streptomyces lividans (Xln10A). The complex was found able to catalyze the selective photo-induced oxidation of organic substrates in the presence of [RuII(bpy)3]2+ as a photosensitizer and [CoIII(NH3)5Cl]2+ as a sacrificial electron acceptor, using water as oxygen atom source. The two published reviews describe different subjects with interest in the fields of biocatalysis and mix metallic-biocatalysis, respectively. The review by Anika Scholtissek et al. describes the state-of-the-art regarding ene-reductases from the old yellow enzyme family (OYEs) to catalyze the asymmetric hydrogenation of activated alkenes to produce chiral products with industrial interest. The dependence of OYEs on pyridine nucleotide coenzyme can be avoided by using nicotinamide coenzyme mimetics. In the review, three main classes of OYEs are described and characterized. The review by Yajie Wang and Huimin Zhao highlights some of the recent examples in the past three years that combine transition metal catalysis with enzymatic catalysis. With recent advances in protein engineering, catalyst synthesis, artificial metalloenzymes, and supramolecular assembly, there is great potential to develop more sophisticated tandem chemoenzymatic processes for the synthesis of structurally complex chemicals. In conclusion, these nine publications give an overview of the possibilities of different catalysts, both traditional biocatalysts and hybrids with metals or organometallic complexes to be used in different processes—particularly in synthetic reactions—under very mild reaction conditions.