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Development Of A Unified Strategy To The C18 C19 And C20 Diterpenoid Alkaloids
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Book Synopsis Development of a Unified Strategy to the C18-, C19-, and C20-Diterpenoid Alkaloids by : Christopher James Marth
Download or read book Development of a Unified Strategy to the C18-, C19-, and C20-Diterpenoid Alkaloids written by Christopher James Marth and published by . This book was released on 2015 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1 of this dissertation lays the foundation for understanding the role diterpenoid alkaloid natural products could play in the development of novel pharmaceuticals and probes for chemical biology applications. The chapter describes ethnomedical uses of Aconitum plants, the bioactivities of select diterpenoid alkaloids, and successful total syntheses of the diterpenoid alkaloids. Chapter 2 details our 'family-oriented' strategy for developing a unified route to the C18-, C19-, and C20-diterpenoid alkaloids. By identifying the common fragments comprising the structural complexity of the diterpenoid alkaloids, we have been able to expedite our retrosynthetic analysis centered on a divergent strategy towards accessing members in each of the families. Chapter 3 describes our efforts at employing the AE ring fragment for the synthesis of the diterpenoid alkaloids. Key to this strategy is the use of a meta-[pi]-arene photocycloaddition reaction for directly constructing the [3.2.1] bicycle of the C18- and C19-diterpenoid alkaloids. Efforts toward accomplishing this objective are detailed herein along with an improved methylenation sequence of the hydrindanone core, a single-step lactone to lactam chemical transformation, and aryl addition attempts to AE bicycle containing substrates. Chapter 4 focuses on our efforts at employing the AEF tricycle in the synthesis of the C18- and C19-diterpenoid alkaloids using cycloaddition strategies. Various meta-[pi]-arene photocycloaddition precursors were synthesized, and a successful substrate was identified. The major differences between the successful and unsuccessful substrates are described in the chapter, as well as efforts towards employing alternative cycloaddition strategies for forging the targeted [3.2.1] bicycle. Chapter 5 details our unified strategy to the diterpenoid alkaloids. Described in this chapter are the rearrangement of the C20-denudatine type [2.2.2] bicycle to the [3.2.1] bicycle of the C18 and C19 natural products, the use of the rearrangement in the synthesis of liljestrandinine (C19), and current work towards the synthesis of weisaconitine D (C18).
Book Synopsis A Ring Expansion Strategy Toward the Synthesis of Hetisine-Type C20-Diterpenoid Alkaloids by : Jessica Kristine Kisunzu
Download or read book A Ring Expansion Strategy Toward the Synthesis of Hetisine-Type C20-Diterpenoid Alkaloids written by Jessica Kristine Kisunzu and published by . This book was released on 2014 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: A benzyne insertion ring expansion strategy toward the synthesis of hetisine-type C20-diterpenoid alkaloids has been developed. The first chapter of this manuscript presents an introduction to C20-diterpenoid alkaloids and previous synthetic work toward selected target core structures. The second and third chapters outline our ring expansion strategy for the synthesis of the core of the natural product cossonidine and efforts to complete its total synthesis. An overview of the structural and biological properties of C20-diterpenoid alkaloids is provided, as well as a survey of the synthetic studies that have been carried out thus far toward natural products containing the hetidine and hetisine-type framework. The two existing syntheses of a hetisine-type diterpenoid alkaloid are also described. This review outlines some of the salient structural challenges associated with the synthesis of these compounds, as well as the strategies applied to their construction. An approach involving a ring expansion was developed to access a tricyclic motif conserved in the hetidine and hetisine frameworks. The acyl-alkylation of aryne intermediates by insertion into C-C sigma bonds was applied to several [beta]-ketoesters and aryne precursors to investigate the efficacy of this transformation on complex systems. Three tricyclic intermediates were synthesized that contain functional handles at the appropriate positions for C-N bond formation to construct the hetisine core. With a sequence in place to arrive as several desired tricyclic intermediates, they were then employed to investigate C-N bond formation. A range of conditions was explored, and the desired azabicycle was accessed in 3 steps from the tricyclic scaffold. The requisite [2.2.2] bicycle was then formed in 2 steps to complete the hetisine core. Finally, the synthetic sequence was modified in order to introduce a methyl group necessary for completion of the natural product target. This methylation pathway has been successful in providing the full hetisine core en route to the synthesis of the natural product cossonidine.
Book Synopsis Synthetic Strategies Toward Aconitine-type and Hetisine-type Diterpenoid Alkaloids by : Jason Jon Pflueger
Download or read book Synthetic Strategies Toward Aconitine-type and Hetisine-type Diterpenoid Alkaloids written by Jason Jon Pflueger and published by . This book was released on 2016 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diterpenoid alkaloid natural products, isolated from plants in the Aconitum, Delphinium, Consolida, and Spiraea genera, possess complex, caged, highly oxygenated skeletons and display potent biological activities through interactions with voltage-gated ion channels. Several of these alkaloids are currently used clinically for the treatment of arrhythmia, while others act as incredibly potent neurotoxins. Until recently, there were very few successful total syntheses of any diterpenoid alkaloid natural products, a testament to the structural complexity of these molecules. We explored synthetic strategies targeting two major types of these natural products: the aconitine-type C19-diterpenoid alkaloids and the hetisine-type C20-diterpenoid alkaloids. Initial work explored Diels-Alder cycloadditions with maleic anhydride-derived dienophiles toward the eventual construction of aconitine-type diterpenoid alkaloids. We examined the selective ring-opening of these adducts with a variety of nucleophiles and utilized an ester-stabilized benzylic nucleophile to achieve C-C bond formation with complete positional selectivity. This product was rapidly elaborated to a vinyl lactone intermediate, which following amine addition and oxidation underwent a high-yielding, diastereoselective methylation reaction to install the challenging C18 carbon atom. Synthesis of the hetisine-type diterpenoid alkaloid cossonidine built off of previous work performed in the Sarpong lab. Reexamining the previously-developed route, we optimized several steps and implemented new reactions to increase the yield and reproducibility of the chemistry and reduce the overall step count. Subsequent functional group transformations involving deprotection and inversion of the C1 hydroxyl group and installation of the allylic alcohol moiety completed the first total synthesis of cossonidine. Recognizing the connections between the various diterpenoid alkaloid types, we explored ways to convert the vinyl lactone intermediate developed in our studies toward aconitine-type natural products into the hetisine-type skeleton of cossonidine. Following the introduction of an iodine atom on the aromatic ring, magnesium-halogen exchange leads to an intramolecular cyclization reaction to forge the central 6-7-6 tricycle with carbonyl groups at all three nitrogen-bearing carbon atoms following oxidation. Efforts to install the C18 methyl group and accomplish a triple reductive amination cascade to complete this second-generation total synthesis are ongoing.
Book Synopsis Total Synthesis of Natural Products by : Jie Jack Li
Download or read book Total Synthesis of Natural Products written by Jie Jack Li and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Total Synthesis of Natural Products' is written and edited by some of today's leaders in organic chemistry. Eleven chapters cover a range of natural products, from steroids to alkaloids. Each chapter contains an introduction to the natural product in question, descriptions of its biological and pharmacological properties and outlines of total synthesis procedures already carried out. Particular emphasis is placed on novel methodologies developed by the respective authors and their research groups. This text is ideal for graduate and advanced undergraduate students, as well as organic chemists in academia and industry.
Book Synopsis Elements of Synthesis Planning by : R. W. Hoffmann
Download or read book Elements of Synthesis Planning written by R. W. Hoffmann and published by Springer Science & Business Media. This book was released on 2009-01-07 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthesis is at the core of organic chemistry. In order for compounds to be studied—be it as drugs, materials, or because of their physical properties— they have to be prepared, often in multistep synthetic sequences. Thus, the target compound is at the outset of synthesis planning. Synthesis involves creating the target compound from smaller, readily available building blocks. Immediately, questions arise: From which bui- ing blocks? In which sequence? By which reactions? Nature creates many highly complex “natural products” via reaction cascades, in which an asso- ment of starting compounds present within the cell is transformed by speci c (for each target structure) combinations of modular enzymes in speci c - quences into the target compounds [1, 2]. To mimic this ef ciency is the dream of an ideal synthesis [2]. However, we are at present so far from - alising such a “one-pot” operation that actual synthesis has to be achieved via a sequence of individual discrete steps. Thus, we are left with the task of planning each synthesis individually in an optimal fashion. Synthesis planning must be conducted with regard for certain speci - tions, some of which are due to the structure of the target molecule, and some of which relate to external parameters such as costs, environmental compatibility, or novelty. We will not consider these external aspects in this context. Planning of a synthesis is based on a pool of information regarding chemical reactions that can be executed reliably and in high chemical yield.
Download or read book Natural Products written by Lixin Zhang and published by Springer Science & Business Media. This book was released on 2007-11-17 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fresh examination of the past successes of natural products as medicines and their new future from both conventional and new technologies. High-performance liquid chromatography profiling, combinatorial synthesis, genomics, proteomics, DNA shuffling, bioinformatics, and genetic manipulation all now make it possible to rapidly evaluate the activities of extracts as well as purified components derived from microbes, plants, and marine organisms. The authors apply these methods to new natural product drug discoveries, to microbial diversity, to specific groups of products (Chinese herbal drugs, antitumor drugs from microbes and plants, terpenoids, and arsenic compounds), and to specific sources (the sea, rainforest, and endophytes). These new opportunities show how research and development trends in the pharmaceutical industry can advance to include both synthetic compounds and natural products, and how this paradigm shift can be more productive and efficacious.
Book Synopsis Trease and Evans' Pharmacognosy by : William Charles Evans
Download or read book Trease and Evans' Pharmacognosy written by William Charles Evans and published by Elsevier Health Sciences. This book was released on 2009-05-27 with total page 3322 pages. Available in PDF, EPUB and Kindle. Book excerpt: This encyclopedic reference work on pharmacognosy covers the study of those natural substances, principally plants, that find a use in medicine. Its popularity and longevity stem from the book's balance between classical (crude and powdered drugs' characterization and examination) and modern (phytochemistry and pharmacology) aspects of this branch of science, as well as the editor's recognition in recent years of the growing importance of complementary medicines, including herbal, homeopathic and aromatherapy. No other book provides such a wealth of detail. A reservoir of knowledge in a field where there is a resurgence of interest - plants as a source of drugs are of growing interest both in complementary medicine fields and in the pharmaceutical industry in their search for new 'lead compounds'. Dr Evans has been associated with the book for over 20 years and is a recognised authority in all parts of the world where pharmacognosy is studied, his knowledge and grasp of the subject matter is unique. Meticulously referenced and kept up to date by the editor, new contributors brought in to cover new areas. New chapter on 'Neuroceuticals'. Addition of many new compounds recently added to British Pharmacopoeia as a result of European harmonisation. Considers development in legal control and standardisation of plant materials previously regarded as 'herbal medicines'. More on the study of safety and efficacy of Chinese and Asian drugs. Quality control issues updated in line with latest guidelines (BP 2007).
Download or read book Name Reactions written by Jie Jack Li and published by Springer Science & Business Media. This book was released on 2010-03-14 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book differs from others on name reactions in organic chemistry by focusing on their mechanisms. It covers over 300 classical as well as contemporary name reactions. Biographical sketches for the chemists who discovered or developed those name reactions have been included. Each reaction is delineated by its detailed step-by-step, electron-pushing mechanism, supplemented with the original and the latest references, especially review articles. This book contains major improvements over the previous edition and the subject index is significantly expanded.
Book Synopsis The logic of chemical synthesis by : E.J. Corey
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 Nitrogen NMR written by M. Witanowski and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: To date nitrogen NMR has been discussed in research papers and review articles throughout the scientific literature. It has been our aim in preparing this book to provide a comprehen sive account of the widely spread applications of nitrogen NMR. The relevant literature has been surveyed from the beginnings of NMR until early 1972. The steady annual growth in the number of references cited since 1965 is ample evidence of the ever increasing importance of the subject. Sufficient theoretical and experimental background is given for an understanding of the applications dealt with in later chapters. The basic principles of NMR are developed with a theoretical approach to chemical shifts and spin-spin coupling constants, particular emphasis being given to nitrogen nuclei. Following this the experimental aspects of nitrogen NMR are adequately described. Special emphasis is given to the observable effects of the nuclear quadrupole moment of the 14 N nucleus. It is appro priate that this topic be dealt with in depth since quadrupolar interactions frequently dominate the information available from a study of the 14 N nucleus and other nuclei spin coupled to it. The applications of nitrogen chemical shift data to organic and inorganic molecules are covered in two extensive chapters which include the effects of paramagnetism on nitrogen NMR.
Download or read book Pharmacognosy written by G. E. Trease and published by Saunders. This book was released on 1983 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plants and their structures. From plant to phytopharmaceutical. Orders and families of plants: recent research references. Phytochemistry. Drugs of biological origin. Microscopical analysis and commercial fibres.
Book Synopsis Efficiency in Natural Product Total Synthesis by : Pei-Qiang Huang
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
Book Synopsis Innovations in Chemical Biology by : Bilge Sener
Download or read book Innovations in Chemical Biology written by Bilge Sener and published by Springer Science & Business Media. This book was released on 2008-11-23 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes 49 chapters presented as plenary , invited lectures and posters at the conference. Six plenary lectures have published in an issue of Pure and Applied Chemistry, Vol. 79, No. 12, 2007; the titles of these presentations are given as an Annex at the end of the book. I thank all contrib utors for the preparation of their presentations. It is sad to report that Professor Hitoshi Ohtaki, one of the founders of the Eurasia conferences and contributors passed away on November 5, 2006. Professor Ohtaki enthusiastically promoted international cooperation and took it upon himself to p- licize Japanese science to the wider world. His contribution in this book will serve as a memorable contribution to that goal. He will be missed by all of us. This book is dedicated to his memory. Professor Dr . Bilge S ̧ ener Editor Memorial Tribute to Professor Dr. Hitoshi Ohtaki Curriculum Vitae of Hitoshi Ohtaki Date of Birth September 16, 1932 Place of Birth T ok yo, Japan Date of Decease November 5, 2006 (at the age of 74) Addr ess 3-9-406 Namiki-2-chome, Kanazawa-ku, Yokohama, Japan Institution Chair Professor of The Research Organization of Science and Engineering, Ritsumeikan University Guest Professor of Yokohama City University Education Bachelor of Science, Nagoya University, 1955 Master of Science, Nagoya University, 1957 Doctor of Science, Nagoya University, 1961 ix x Memorial Tribute to Professor Dr.
Book Synopsis Organic Synthesis Highlights by : Hans-Josef Altenbach
Download or read book Organic Synthesis Highlights written by Hans-Josef Altenbach and published by John Wiley & Sons. This book was released on 2008-11-20 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unusual collection of 49 essays gives an overview of the trends and accomplishments of synthetic organic chemistry in recent years. Unique in its approach, it deals with almost every aspect of modern synthesis. The first part of the book describes methods and reagents, with particular emphasis on rapidly developing organometallic and biooriented procedures. In the second part, these tools are applied to the syntheses of interesting target compounds and natural compounds with remarkable physiological properties. Mechanistic discussions and retrosynthetic analyses are included. More than 1000 up-to-date references help the reader to pursue the topics highlighted here. This book gives both the active researcher and the advanced student insight into the competitive atmosphere, creativity, and resourcefulness so characteristic of organic synthesis today.
Book Synopsis Asymmetric Dearomatization Reactions by : Shu-Li You
Download or read book Asymmetric Dearomatization Reactions written by Shu-Li You and published by John Wiley & Sons. This book was released on 2016-09-13 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first comprehensive account of the rapidly growing field of asymmetric dearomatization reactions with a focus on catalytic methods. It introduces the concept of dearomatization and describes recent progress in asymmetric reaction procedures with different catalyst systems, such as organocatalysts, transition metal catalysts, and enzymes. Chapters on dearomatizations of electron-deficient aromatic rings, dearomatization reactions via transition metal-catalyzed cross-couplings as well as dearomatization strategies in the synthesis of complex natural products are also included. Written by pioneers in the field, this is a highly valuable source of information not only for professional synthetic chemists in academia and industry but also for all those are interested in asymmetric methodologies and organic synthesis in general.
Book Synopsis The Application of Green Solvents in Separation Processes by : Francisco Pena-Pereira
Download or read book The Application of Green Solvents in Separation Processes written by Francisco Pena-Pereira and published by Elsevier. This book was released on 2017-02-28 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Application of Green Solvents in Separation Processes features a logical progression of a wide range of topics and methods, beginning with an overview of green solvents, covering everything from water and organic solvents, to ionic liquids, switchable solvents, eutectic mixtures, supercritical fluids, gas-expanded solvents, and more. In addition, the book outlines green extraction techniques, such as green membrane extraction, ultrasound-assisted extraction, and surfactant-mediated extraction techniques. Green sampling and sample preparation techniques are then explored, followed by green analytical separations, including green gas and liquid capillary chromatography, counter current chromatography, supercritical fluid chromatography, capillary electrophoresis, and other electrical separations. Applications of green chemistry techniques that are relevant for a broad range of scientific and technological areas are covered, including the benefits and challenges associated with their application. - Provides insights into recent advances in greener extraction and separation processes - Gives an understanding of alternatives to harmful solvents commonly used in extraction and separation processes, as well as advanced techniques for such processes - Written by a multidisciplinary group of internationally recognized scientists
Book Synopsis The Optical Clearing Method by : Luís Manuel Couto Oliveira
Download or read book The Optical Clearing Method written by Luís Manuel Couto Oliveira and published by Springer Nature. This book was released on 2019-11-27 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the Optical Immersion Clearing method and its application to acquire information with importance for clinical practice and various fields of biomedical engineering. The method has proved to be a reliable means of increasing tissue transparency, allowing the investigator or surgeon to reach deeper tissue layers for improved imaging and laser surgery. This result is obtained by partial replacement of tissue water with an active optical clearing agent (OCA) that has a higher refractive index and is a better match for the refractive index of other tissue components. Natural tissue scattering is thereby reduced. An exponential increase in research using this method has occurred in recent years, and new applications have emerged, both in clinical practice and in some areas of biomedical engineering. Recent research has revealed that treating ex vivo tissues with solutions containing active OCAs in different concentrations produces experimental data to characterize drug delivery or to discriminate between normal and pathological tissues. The obtained drug diffusion properties are of interest for the pharmaceutical and organ preservation industry. Similar data can be estimated with particular interest for food preservation. The free water content evaluation is also of great interest since it facilitates the characterization of tissues to discriminate pathologies. An interesting new application that is presented in the book regards the creation of two optical windows in the ultraviolet spectral range through the application of the immersion method. These induced transparency windows open the possibility to diagnose and treat pathologies with ultraviolet light. This book presents photographs from the tissues we have studied and figures that represent the experimental setups used. Graphs and tables are also included to show the numerical results obtained in the sequential calculations performed.
