Download or read book Transition Metal Catalyzed Cyclization and Synthesis of Triptolide Analogs written by Jiehui Pan and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Transition Metal Catalyzed Cyclization and Synthesis of Triptolide Analogs" by Jiehui, Pan, 潘杰輝, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled TRANSITION METAL CATALYZED CYCLIZATION AND SYNTHESIS OF TRIPTOLIDE ANALOGS Submitted by Pan Jiehui for the Degree of Doctor of Philosophy at The University of Hong Kong in March 2006 (-)-Triptonide, (-)-triptolide, and 16-hydroxytriptolide are bioactive natural product, isolated from the Chinese medicinal plant Tripterygium wilfordii Hook. F. (Lei Gong Teng). They show potent immunosuppressive, antileukemic, and antifertile activities. However, their mechanisms of actions still remain elusive, and only limited structure-activity relationship studies of triptolide and its analogs have been carried out. I have successfully synthesized bioactive alkyne-derived triptolide probe and azide functionalized fluorophore tags, which were designed for identifying the receptors of triptolide by using the click chemistry method. A model reaction simulating the cycloaddition between the bioactive triptolide probe and rhodamine tag has been successfully accomplished, which could be applied in the search for the receptors of triptolide. Synthetic studies of triptolide analogs could provide new methods to prepare analogs containing moieties different from the original triptolide molecule, and possibly enable its curative effects to be distinguished from its toxic effects. Two efficient cross-coupling methods including the Heck reaction and the Sonogashira coupling have been utilized for the introduction of the C-13 side chain of triptolide analogs. These protocols provide new ways to modify the triptolide molecule at the C-13 position in addition to the Claisen rearrangement. Several novel dimeric triptolide analogs with different functionalities at the C-13 position have been prepared. The exploration of transition metal-catalyzed cyclization reactions has been at the frontier of organic synthesis. I have prepared several sterically bulky N, N'-disubstituted cyclic thiourea-gold(I) complexes. The crystal structures of the complexes reveal the different coordination nature of sulphur in these complexes in the solid state. In solution, a ligand scrambling reaction has been observed with the N, N'-dialkyl cyclic thiourea ligands. Useful information about the equilibrium of ligand scrambling reaction has been obtained from the H NMR experiments. I have used bulky N, N'-disubstituted cyclic thioureas as effective ligands for the Au(I)-catalyzed carbocyclization of 1,3-dicarbonyl compounds with alkynes. The reactions can be readily conducted with a low catalyst loading, short reaction time in an "open flask" system and in high yields. In addition, I have demonstrated an application of the bulky N, N'-disubstituted cyclic thiourea-Au(I) complexes in the cycloisomerization of acetylenic 1,3-dicarbonyl compounds to form γ-lactones and γ-lactams. These reactions can be readily conducted with low catalytic loading in an "open flask" system and provide a new method to generate γ-lactones and γ-lactams. DOI: 10.5353/th_b3776596 Subjects: Ring formation (Chemistry) Bioactive compounds - Synthesis Transition metal catalysts
Download or read book Transition Metal Catalyzed Cyclization and Synthesis of Triptolide Analogs written by Jiehui Pan and published by . This book was released on 2006 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recent Developments in the Synthesis of Heterocycles by Transition metal Catalyzed Cyclization Reactions written by Bartolo Gabriele and published by . This book was released on 2006 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Towards a Formal Total Synthesis of Triptolide Via a Gold catalyzed Cyclization Cascade written by Travis R. Schwantje and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis discusses the progress made towards a formal total synthesis of triptolide, a naturally occurring diterpenoid triepoxide molecule. Isolated from a Chinese vine, triptolide features some interesting structural characteristics and has demonstrated a broad range of interesting medicinal effects. It has demonstrated remarkable cytotoxicity against a number of cancer cell lines, immunosuppressive activity, and reversible male sterility. This biological activity has made it a target of a number of total syntheses spanning from 1980 to 2010. Gold-catalyzed transformations are an emerging field in synthetic organic chemistry, but their efficacy and potential uses are gaining much recognition among the synthetic organic community. Our research group is extremely interested in the applications of such gold-catalyzed organic transformations in natural product synthesis. Here, we discuss our investigations towards accessing the tetracyclic core of triptolide using a gold-catalyzed cyclization cascade reaction. We explored a number of synthetic routes towards a common linear precursor, and our successes and failures are discussed herein. We also report numerous unsuccessful efforts towards an oxidative gold-catalyzed cyclization cascade to form the tetracyclic core of triptolide. Finally, we investigated the use of a photocatalytic radical cyclization cascade to access the desired core. We report some promising preliminary results, and this study is ongoing in the Barriault group.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The logic of chemical synthesis written by E.J. Corey and published by Рипол Классик. This book was released on 1991 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Natural Terpenoids as Messengers written by Paul Harrewijn and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: In contrast to books on specific bioactive compounds, this book deals with the role of mevalonic acid metabolites (isoprenoids and their derived structures) in metabolism, development, and functions of organisms, which, though diverse, show various levels of communication. Different disciplines are brought together in a discussion of the messenger functions of terpenoids within and between organisms belonging to five biological kingdoms: bacteria, fungi, plants, insects, and vertebrates (including humans). The present volume covers evolutionary aspects of terpenoids in plant physiology, plant-insect relationships, semiochemicals, and in life sciences, with special emphasis on cancer research and treatment. The book provides proposals for multidisciplinary model systems for the study of interrelationships of organisms utilizing terpenoid messengers, and discusses novel strategies for insect control and multifactor treatments of cancer utilizing terpenoids. This book is of interest to scientists, and students at an advanced level: biologists, plant breeders, pharmacologists, specialists in medical fields, especially oncologists, physicians in general, and anyone with a basic biochemical and physiological knowledge.
Download or read book Biotechnology of Natural Products written by Wilfried Schwab and published by Springer. This book was released on 2017-11-16 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text comprehensively covers the analysis, enzymology, physiology and genetics of valuable natural products used in the food industry that are attractive targets for biotechnological production. The focus is on the recent advances made to achieve this goal. This unique work is the first book to focus on biotechnological production of important natural products in food additives, fragrances and flavorings, and other bioactive compounds in food. The chapters offer a deep insight into modern research and the development of low molecular weight natural products. Biotechnology of Natural Products covers products in the Phenolic, Terpenoid, and Alkaloid categories, providing a full overview of the biotechnology of food additives and other low molecular weight natural products. Gene clustering and the evolution of pathways are covered, as well as future perspectives on the topic. Due to limited oil resources and increasing consumer demand for naturalness, bioprocesses are increasingly needed to meet these requirements. Novel sophisticated technologies have facilitated the elucidation of new chemical molecules, their biosynthetic pathways and biological functions. This book provides researchers with a full overview of the technologies and processes involved in the biotechnology of natural products.
Download or read book Chiral Lewis Acids in Organic Synthesis written by Jacek Mlynarski and published by John Wiley & Sons. This book was released on 2017-10-23 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete overview covering the application of metal-based chiral Lewis acids from all parts of the periodic table, the Author emphasizes the most recent contributions to the field as well as prominent direction of development. The book discusses the design of chiral complexes as well as a wide spectrum of reactions promoted by various chiral Lewis acids, including water-compatible acids as well as the most important applications in the chemical and pharmaceutical industries. A must-have for catalytic and organic chemists working in the field, both in academia and industry, as well as pharmaceutical and medicinal chemists.
Download or read book Biological Inorganic Chemistry written by Robert R. Crichton and published by Elsevier. This book was released on 2007-12-11 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of metals in biology, the environment and medicine has become increasingly evident over the last twenty five years. The study of the multiple roles of metal ions in biological systems, the rapidly expanding interface between inorganic chemistry and biology constitutes the subject called Biological Inorganic Chemistry. The present text, written by a biochemist, with a long career experience in the field (particularly iron and copper) presents an introduction to this exciting and dynamic field. The book begins with introductory chapters, which together constitute an overview of the concepts, both chemical and biological, which are required to equip the reader for the detailed analysis which follows. Pathways of metal assimilation, storage and transport, as well as metal homeostasis are dealt with next. Thereafter, individual chapters discuss the roles of sodium and potassium, magnesium, calcium, zinc, iron, copper, nickel and cobalt, manganese, and finally molybdenum, vanadium, tungsten and chromium. The final three chapters provide a tantalising view of the roles of metals in brain function, biomineralization and a brief illustration of their importance in both medicine and the environment. Relaxed and agreeable writing style. The reader will not only fiind the book easy to read, the fascinating anecdotes and footnotes will give him pegs to hang important ideas on.Written by a biochemist. Will enable the reader to more readily grasp the biological and clinical relevance of the subject.Many colour illustrations. Enables easier visualization of molecular mechanismsWritten by a single author. Ensures homgeneity of style and effective cross referencing between chapters
Download or read book Comprehensive Organic Reactions in Aqueous Media written by Chao-Jun Li and published by John Wiley & Sons. This book was released on 2007-06-04 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extensive update of the classic reference on organic reactions in water Published almost a decade ago, the first edition has served as the guide for research in this burgeoning field. Due to the cost, safety, efficiency, and environmental friendliness of water as a solvent, there are many new applications in industry and academic laboratories. More than forty percent of this extensively updated second edition covers new reactions. For ease of reference, it is organized by functional groups. A core reference, Comprehensive Organic Reactions in Aqueous Media, Second Edition: * Provides the most comprehensive coverage of aqueous organicreactions available * Covers the basic principles and theory and progresses to applications * Includes alkanes, alkenes, aromatics, electrophilic substitutions, carbonyls, alpha, beta-unsaturated carbonyls, carbon-nitrogen bonds, organic halides, pericyclic reactions, photochemical reactions, click chemistry, and multi-step syntheses? * Provides examples of applications in industry This is the premier reference for chemists and chemical engineers in industry or research, as well as for students in advanced-level courses.
Download or read book Structural and Mechanistic Enzymology written by and published by Academic Press. This book was released on 2017-07-17 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural and Mechanistic Enzymology, Volume 109, the latest release in the Advances in Protein Chemistry and Structural Biology series, is an essential resource for protein chemists. Chapters in this new volume include Collagenolytic Matrix Metalloproteinase Structure–Function Relationships: Insights from Molecular Dynamics Studies, Computational Glycobiology: Mechanistic Studies of Carbohydrate-Active Enzymes and Implication for Inhibitor Design, Computational Biochemistry-Enzyme Mechanisms Explored, and A Paradigm for C-H Bond Cleavage: Structural and Functional Aspects of Transition State Stabilization by Mandelate Racemase. This series presents new information on protocols and analysis of proteins, with each volume guest edited by leading experts in a broad range of protein-related topics. This volume presents state-of-the-art contributions, providing insights into the relationship between enzyme structure, catalysis, and function. Provides cutting-edge developments in protein chemistry and structural biology Features new information about protocols and analysis of proteins Contains chapters written by authorities in their respective fields Targeted to a wide audience of researchers, specialists and students
Download or read book Advances in Pharmaceutical Biotechnology written by Jayanta Kumar Patra and published by Springer Nature. This book was released on 2020-03-30 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explains both the basic science and the applications of biotechnology-derived pharmaceuticals, with special emphasis on their clinical uses. The foundations of pharmaceutical biotechnology lie mainly in the capability of plants, microorganism, and animals to produce low and high molecular weight compounds useful as therapeutics. Pharmaceutical biotechnology has flourished since the advent of recombinant DNA technology and metabolic engineering, supported by the well-developed bioprocess technology. A large number of monoclonal antibodies and therapeutic proteins have been approved, delivering meaningful contributions to patients’ lives, and the techniques of biotechnology are also a driving force in modern drug discovery. Due to this rapid growth in the importance of biopharmaceuticals and the techniques of biotechnologies to modern medicine and the life sciences, the field of pharmaceutical biotechnology has become an increasingly important component in the education of pharmacists and pharmaceutical scientists. This book will serve as a complete one-stop source on the subject for undergraduate and graduate pharmacists, pharmaceutical science students, and pharmaceutical scientists in industry and academia.
Download or read book Efficiency in Natural Product Total Synthesis written by Pei-Qiang Huang and published by John Wiley & Sons. This book was released on 2018-07-24 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Uniting the key organic topics of total synthesis and efficient synthetic methodologies, this book clearly overviews synthetic strategies and tactics applied in total synthesis, demonstrating how the total synthesis of natural products enables scientific and drug discovery. • Focuses on efficiency, a fundamental and important issue in natural products synthesis that makes natural product synthesis a powerful tool in biological and pharmaceutical science • Describes new methods like organocatalysis, multicomponent and cascade reactions, and biomimetic synthesis • Appeals to graduate students with two sections at the end of each chapter illustrating key reactions, strategies, tactics, and concepts; and good but unfinished total synthesis (synthesis of core structure) before the last section • Compiles examples of solid phase synthesis and continuing flow chemistry-based total synthesis which are very relevant and attractive to industry R&D professionals
Download or read book Organic Reactions in Water written by U. Marcus Lindstrom and published by John Wiley & Sons. This book was released on 2008-04-15 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volatile organic solvents are the normal media used in both research scale and industrial scale synthesis of organic chemicals. Their environmental impact is significant, however, and so the development of alternative reaction media has become of great interest. Developments in the use of water as a solvent for organic synthesis have reached the point where it could now be considered a viable solvent for many organic reactions. Organic Reactions in Water demonstrates the underlying principles of using water as a reaction solvent and, by reference to a range of reaction types and systems, it’s effective use in synthetic organic chemistry. Written by an internationally respected team of contributors, and with a strong focus on the practical use of water as a reaction medium, this book illustrates the enormous potential of water for the development of new and unique chemistries and synthetic strategies, while at the same time offering a much reduced environmental impact.
Download or read book Free Radicals in Solution written by Cheves Walling and published by . This book was released on 2013-02 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Dissertation Index Chemistry P Z written by and published by . This book was released on 1984 with total page 844 pages. Available in PDF, EPUB and Kindle. Book excerpt:
