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Synthetic Studies Towards Aryl Spiroketals Related To Benzannulated Spiroketal Containing Natural Products
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Book Synopsis Synthetic Studies Towards Aryl Spiroketals Related to Benzannulated Spiroketal-containing Natural Products by : Yen-Cheng (William) Liu
Download or read book Synthetic Studies Towards Aryl Spiroketals Related to Benzannulated Spiroketal-containing Natural Products written by Yen-Cheng (William) Liu and published by . This book was released on 2009 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Synthetic Studies Towards 5,5-Benzannulated Spiroketals Isolated from Traditional Chinese Medicines by : Daniel Chorley
Download or read book Synthetic Studies Towards 5,5-Benzannulated Spiroketals Isolated from Traditional Chinese Medicines written by Daniel Chorley and published by . This book was released on 2015 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes synthetic endeavours towards two families of 5,5-benzannulated spiroketals isolated from plants used in traditional Chinese medicine: the danshenspiroketallactones and the pinnatifinosides. The first part of this thesis describes the successful synthesis of danshenspiroketallactone (14) and epi-danshenspiroketallactone (15). Danshenspiroketallactone (14) was isolated in 1985 by Rao et al. from Chinese Sage (Salvia miltiorrhiza), a plant used in traditional Chinese medicine to treat cardiovascular disease. In 1988 epi-danshenspiroketallactone (15) was isolated from S. miltiorrhiza by Snyder et al. These natural products possess a 5,5-spiroketallactone moiety fused to a naphthalene ring and are epimeric at the spiroketal centre. Key features of the total synthesis described herein are a directed ortho-metalation/lactonisation procedure used to unite the aromatic and aliphatic fragments of the molecule and form the lactone ring, and an oxidative radical cyclisation by intramolecular hydrogen abstraction used to complete the spiroketal. The second part of this thesis presents synthetic attempts towards pinnatifinosides C (18) and D (19), two members of the pinnatifinosides family of 5,5-spiroketal flavone containing natural products isolated by Zhang et al. in 2001 from Chinese Hawthorn (Crataegus pinnatifida). Two benzannulated spiroketal model compounds possessing the core of the pinnatifinosides were synthesised using a key Sonogashira cross-coupling reaction and gold-catalysed spiroketalisation. While the final spiroketalisation step of the attempted total synthesis of pinnatifinosides C (18) and D (19) using methods developed during the initial model studies proved unsuccessful, these investigations have established a sound platform that will enable further synthetic efforts towards pinnatifinosides C (18) and D (19), and other related compounds.
Book Synopsis Studies on the Stereoselective Synthesis of Glycal-derived Spiroketals by : Jacqueline M. Wurst
Download or read book Studies on the Stereoselective Synthesis of Glycal-derived Spiroketals written by Jacqueline M. Wurst and published by . This book was released on 2012 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes our studies on the synthesis of spiroketals by intramolecular spirocyclization of glycal epoxide substrates. First, a 68-membered library of stereochemically complex benzannulated spiroketals was synthesized for discovery screening. The library was prepared by stereoselective epoxidation of glycals followed by kinetically-controlled spirocyclization of benzannulated sidechain alcohols. The activity of individual library members in various assays suggests that stereochemistry, spiroketal ring size, and position of the aromatic ring are critical factors for binding to targets. Next, using a panel of electronically diverse benzannulated substrates, we studied the mechanism of a MeOH-catalyzed epoxide-opening spirocyclization with inversion of configuration. Our results indicate that MeOH is second-order catalyst in the desired spirocyclization, while acetone from the DMDO reagent is a first-order inhibitor. Finally, we have developed an efficient synthetic approach toward the renal-protective spiroketal natural products acortatarins A and B. The key step is a reductive spirocyclization reaction of a glycal epoxide and a pendant aldehyde nucleophile.
Book Synopsis Synthetic Studies Towards Aromatic Polyketide Derived Natural Products by : Peter Jaein Choi
Download or read book Synthetic Studies Towards Aromatic Polyketide Derived Natural Products written by Peter Jaein Choi and published by . This book was released on 2011 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The first part of this thesis describes the successful synthesis of a series of 6,6- bisbenzannulated spiroketal analogues of the rubromycin family. The synthesis of spiroketals 183a-183e and spiroaminal 237 were successfully executed using a novel microwave-assisted DIHMA approach. Coupling of an aryl acetylene and an aryl aldehyde via acetylide anion addition resulted in the formation of an alkynol which was followed by oxidation to the desired ynone. Spirocyclisation using the DIHMA protocol afforded the desired bisbenzannulated spiroketals 183a-183e and spiroaminal 237 in good yields. Hydroxy-substituted 6,6- bisbenzannulated spiroketal 182 was successfully furnished by the reduction of ketosubstituted 6,6-bisbenzannulated spiroketal 183a with sodium borohydride. The second part of this research presents synthetic attempts to access the chiral 3-substituted phthalide containing natural products; aigialospirol (256) and herbaric acid (255). The synthesis of chiral vinylphthalide 406 proved challenging and was overcome by the use of a microwave-assisted chemoenzymatic resolution to install the C3 stereocenter of phthalide 406. Despite various attempts to functionalise vinylphthalide 406 towards the synthesis of aigialospirol, results were unsuccessful. With chiral vinylphthalide 406 in hand, the first synthesis and the structural assignment of ( -- )-herbaric acid (255) was accomplished. This was achieved via heteroatom-directed Wacker oxidation on vinylphthalide 406 to form aldehyde 460. Aldehyde 460 underwent smooth oxidation with Oxone® affording acid 488 which underwent facile methyl ester formation to facilitate purification, thus delivering enantioenriched lactone ester 489. Smooth demethylation with concomitant ester hydrolysis was effected by boron tribromide to give ( -- )-herbaric acid (255). The realisation of this entirely regioselective anti-Markovnikov addition of water during the Wacker oxidation provides a mild alternative to hydroboration/oxidation protocols that are traditionally used for terminal alkenes"--Abstract.
Book Synopsis Studies Toward the Total Synthesis of Spiroketal Containing Natural Products by : Rosemary O'Mahony
Download or read book Studies Toward the Total Synthesis of Spiroketal Containing Natural Products written by Rosemary O'Mahony and published by . This book was released on 1988 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Synthetic Studies on the Spongistatin Family of Natural Products by : Clay S. Bennett (III.)
Download or read book Synthetic Studies on the Spongistatin Family of Natural Products written by Clay S. Bennett (III.) and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Synthetic Studies Towards the Gombaspiroketals and a Cobalt-catalysed Epoxide Olefination by : Megan Lee Quach
Download or read book Synthetic Studies Towards the Gombaspiroketals and a Cobalt-catalysed Epoxide Olefination written by Megan Lee Quach and published by . This book was released on 2019 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: The gombaspiroketals (14–16) are 6,6-spiroketal-containing natural products, which were isolated from a South Korean marine sponge (Clathria gombawuiensis) in 2014. The gombaspiroketals belong to a family of sesterterpenoids derived from the alotane skeleton, some of which exhibit potent and varied bioactivities. Recent total syntheses of alotane natural products has demonstrated the importance of total synthesis efforts in furthering the field of organic chemistry, and for investigating structure-activity relationships and biological properties. Therefore the gombaspiroketals were chosen as a target for synthetic studies. Epoxide 171 was identified as a possible intermediate towards the gombaspiroketals, which was envisioned to be accessed by Hosomi-Sakurai allylation of allylsilane 45 and cyclic acetal 172 followed by epoxidation. This work describes efforts in the syntheses of allylsilane 45 and cyclic acetal 172. Towards allylsilane 45, the literature cuprate conjugate addition of bromide 54 with acrylate 55 was irreproducible, affording ester 56 in varying yields of 0–66%. Alternative transformations were investigated for access to ester 56, including addition of organometallic nucleophiles and transition metal catalysis. Although no method was found to provide reliable access to 56 in consistently good yield, the cobalt- and nickel-catalysed conjugate additions emerged as potential alternatives worthy of further investigation. Subsequent elaboration to allylsilane 45 via intramolecular Horner-Wadsworth-Emmons reaction of 58 proceeded smoothly. Synthesis of aldehyde 303 en route to acetal 172 was investigated. The literature sequence reported from 2-methylcyclohexanone (299) was ineffective, due to presence of inseparable impurities in the final products. 303 was obtained in excellent purity by intramolecular Horner-Wadsworth-Emmons reaction of phosphonate 345 which was reliably accessed on large scale. Aldehyde 303 was unified with phosphonium 358 (derived from lactone 359) by phosphoniosilylation alkylation. Subsequent conjugate addition of a methyl group to 357 was unsuccessful, due to the preference for isomerisation to 1,3-dienes. Model cyclic acetals 415 and 416 were prepared from 357 instead, for use in model allylations with alyllsilane 45. Alongside synthetic studies towards the gombaspiroketals, a cobalt-catalysed epoxide olefination to homoallylic alcohols was investigated. This thesis describes the discovery, synthetic utility, and mechanistic considerations of this novel methodology.
Book Synopsis Synthetic Studies Towards the Spiroketal Fragments of the Spongistatins by : Ronald Zemribo
Download or read book Synthetic Studies Towards the Spiroketal Fragments of the Spongistatins written by Ronald Zemribo and published by . This book was released on 1998 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Strategies and Tactics in Organic Synthesis by : Michael Harmata
Download or read book Strategies and Tactics in Organic Synthesis written by Michael Harmata and published by Elsevier. This book was released on 2015-08-13 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: Strategies and Tactics in Organic Synthesis provides a forum for investigators to discuss their approach to the science and art of organic synthesis. Rather than a simple presentation of data or a secondhand analysis, this classic provides stories that vividly demonstrate the power of the human endeavor known as organic synthesis and the creativity and tenacity of its practitioners. Firsthand accounts of each project tell of the excitement of conception, the frustration of failure, and the joy experienced when either rational thought or good fortune gives rise to the successful completion of a project. This book series shows how synthesis is really done. Readers will be educated, challenged, and inspired by these accounts, which portray the idea that triumphs do not come without challenges. This innovative approach also helps illustrate how challenges to further advance the science and art of organic synthesis can be overcome, driving the field forward to meet the demands of society by discovering new reactions, creating new designs, and building molecules with atom and step economies that provide functional solutions to create a better world. - Presents state-of-the-art developments in organic synthesis - Provides insight and offers new perspective to problem-solving - Written by leading experts in the field - Uses firsthand narrative accounts to illustrate vividly the challenges and joys involved in advancing the science of organic synthesis
Download or read book Chimie Pure Et Appliquée written by and published by . This book was released on 2012 with total page 924 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Small Molecule Drug Discovery by : Andrea Trabocchi
Download or read book Small Molecule Drug Discovery written by Andrea Trabocchi and published by Elsevier. This book was released on 2019-11-23 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Small Molecule Drug Discovery: Methods, Molecules and Applications presents the methods used to identify bioactive small molecules, synthetic strategies and techniques to produce novel chemical entities and small molecule libraries, chemoinformatics to characterize and enumerate chemical libraries, and screening methods, including biophysical techniques, virtual screening and phenotypic screening. The second part of the book gives an overview of privileged cyclic small molecules and major classes of natural product-derived small molecules, including carbohydrate-derived compounds, peptides and peptidomimetics, and alkaloid-inspired compounds. The last section comprises an exciting collection of selected case studies on drug discovery enabled by small molecules in the fields of cancer research, CNS diseases and infectious diseases. The discovery of novel molecular entities capable of specific interactions represents a significant challenge in early drug discovery. Small molecules are low molecular weight organic compounds that include natural products and metabolites, as well as drugs and other xenobiotics. When the biological target is well defined and understood, the rational design of small molecule ligands is possible. Alternatively, small molecule libraries are being used for unbiased assays for complex diseases where a target is unknown or multiple factors contribute to a disease pathology. - Outlines modern concepts and synthetic strategies underlying the building of small molecules and their chemical libraries useful for drug discovery - Provides modern biophysical methods to screening small molecule libraries, including high-throughput screening, small molecule microarrays, phenotypic screening and chemical genetics - Presents the most advanced chemoinformatics tools to characterize the structural features of small molecule libraries in terms of chemical diversity and complexity, also including the application of virtual screening approaches - Gives an overview of structural features and classification of natural product-derived small molecules, including carbohydrate derivatives, peptides and peptidomimetics, and alkaloid-inspired small molecules
Book Synopsis Comprehensive Heterocyclic Chemistry IV by : David St. Clair Black
Download or read book Comprehensive Heterocyclic Chemistry IV written by David St. Clair Black and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis C-C Bond Activation by : Guangbin Dong
Download or read book C-C Bond Activation written by Guangbin Dong and published by Springer. This book was released on 2014-09-18 with total page 265 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. Review articles for the individual volumes are invited by the volume editors. Readership: research chemists at universities or in industry, graduate students
Author :Gregory Robert James Thatcher Publisher :Washington, DC : American Chemical Society ISBN 13 : Total Pages :716 pages Book Rating :4.:/5 (3 download)
Book Synopsis The Anomeric Effect and Associated Stereoelectronic Effects by : Gregory Robert James Thatcher
Download or read book The Anomeric Effect and Associated Stereoelectronic Effects written by Gregory Robert James Thatcher and published by Washington, DC : American Chemical Society. This book was released on 1871 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discusses contemporary experimental and computational studies on the anomeric effect and related stereoelectronic effects and presents conflicting data and theories in this highly controversial area. Explores applications in carbohydrate chemistry, including enzymology, as well as organometallic chemistry and the chemistry of phosphates and sulfates. Includes examination of molecular modeling methods in compounds influenced by stereoelectronic effects.
Book Synopsis Remote C-H Bond Functionalizations by : Debabrata Maiti
Download or read book Remote C-H Bond Functionalizations written by Debabrata Maiti and published by John Wiley & Sons. This book was released on 2021-04-26 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: A guide to contemporary advancements in the field of distal C-H functionalizations An important and dynamic topic within the modern field of organic synthesis, selective functionalization of C-H bonds can be used in a variety of applications across the pharmaceutical and agrochemical industries. Remote C-H Bond Functionalizations presents an inclusive account of the most recent developments and potential applications of performing variegated functionalizations selectively at the distal positions of organic compounds. Featuring contributions by an international team of experts, this authoritative volume provides deep insight into distal functionalizations, including detailed discussion of mechanisms, the engineering of templates, and the design of strategies. The text covers a diverse range of topics including C-H functionalization of palladium/norbornene catalysis, ruthenium-catalyzed remote functionalization, the non-directed distal C(sp2)-H, functionalization, transition metal catalyzed distal para-selective C-H functionalization, and much more. Reviewing contemporary advancements in the field while laying the foundation for future research, this important resource: Provides the most recent research and thorough coverage of the subject available in a single volume Offers practical information on C-H functionalizations in various industries Includes an up-to-date introduction to distal C-H functionalizations Remote C-H Bond Functionalizations is a must-read for every synthetic chemist, including chemists working with organometallics, organic chemists and researchers, and industrial chemists.
Book Synopsis Ruthenium in Organic Synthesis by : Shun-Ichi Murahashi
Download or read book Ruthenium in Organic Synthesis written by Shun-Ichi Murahashi and published by John Wiley & Sons. This book was released on 2006-03-06 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this comprehensive book, one of the leading experts, Shun-Ichi Murahashi, presents all the important facets of modern synthetic chemistry using Ruthenium, ranging from hydrogenation to metathesis. In 14 contributions, written by an international authorship, readers will find all the information they need about this fascinating and extraordinary chemistry. The result is a high quality information source and a indispensable reading for everyone working in organometallic chemistry. From the contents: Introduction (S.-I. Murahashi) Hydrogenation and Transfer Hydrogenation (M. Kitamura and R. Noyori) Oxidations (S.-I. Murahashi and N. Komiya) Carbon-Carbon Bond Formations via Ruthenacycle Intermediates (K. Itoh) Carbon-Carbon Bond Formation via pi-Allylruthenium Intermediates (T. Mitsudo) Olefin Metathesis (R. H. Grubbs) Cyclopropanation (H. Nishiyama) Nucleophilic Addition to Alkynes and Reactions via Vinylidene Intermediates (P. Dixneuf) Reactions via C-H Activation (N. Chatani) Lewis Acid Reactions (E. P. Kundig) Reactions with CO and CO2 (T. Mitsudo) Isomerization of Organic Substrates Catalyzed by Ruthenium Complexes (H. Suzuki) Radical Reactions (H. Nagashima) Bond Cleavage Reactions (S. Komiya)
Book Synopsis Solid-Phase Peptide Synthesis by : Gregg B. Fields
Download or read book Solid-Phase Peptide Synthesis written by Gregg B. Fields and published by Academic Press. This book was released on 1997-10-21 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt: The critically acclaimed laboratory standard for more than forty years, Methods in Enzymology is one of the most highly respected publications in the field of biochemistry. Since 1955, each volumehas been eagerly awaited, frequently consulted, and praised by researchers and reviewers alike. More than 275 volumes have been published (all of them still in print) and much of the material is relevant even today-truly an essential publication for researchers in all fields of life sciences. Key Features * Solid-phase peptide synthesis * Applications of peptides for structural and biological studies * Characterization of synthetic peptides
