Download or read book Total Synthesis of Bioactive Natural Products by Palladium Catalyzed Domino Cyclization of Allenes and Related Compounds written by Shinsuke Inuki and published by Springer Science & Business Media. This book was released on 2011-11-23 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: The author has developed novel methodologies for highly efficient construction of functionalized heterocycles by palladium-catalyzed domino/cascade cyclization of allenes and related compounds containing appropriate nucleophilic group(s). Based on these methodologies, enantioselective total syntheses of bioactive natural products, pachastrissamine (26% overall yield in seven steps), lysergic acid (4.0% overall yield in fifteen steps), lysergol (3.6% overall yield in fifteen steps) and isolysergol (8.2% overall yield in eleven steps) have been achieved. These are more facile synthetic route than those previously reported. These findings would contribute to the development of efficient synthetic methods for biologically active compounds containing a complex structure.
Download or read book The Total Synthesis of Natural Products written by John ApSimon and published by . This book was released on 1973 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Artificial Metalloenzymes and MetalloDNAzymes in Catalysis written by Montserrat Diéguez and published by John Wiley & Sons. This book was released on 2018-02-21 with total page 1200 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important reference for researchers in the field of metal-enzyme hybrid catalysis Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a comprehensive review of the most current strategies, developed over recent decades, for the design, synthesis, and optimization of these hybrid catalysts as well as material about their application. The contributors—noted experts in the field—present information on the preparation, characterization, and optimization of artificial metalloenzymes in a timely and authoritative manner. The authors present a thorough examination of this interesting new platform for catalysis that combines the excellent selective recognition/binding properties of enzymes with transition metal catalysts. The text includes information on the various applications of metal-enzyme hybrid catalysts for novel reactions, offers insights into the latest advances in the field, and contains an informative perspective on the future: Explores the development of artificial metalloenzymes, the modern and strongly evolving research field on the verge of industrial application Contains a comprehensive reference to the research area of metal-enzyme hybrid catalysis that has experienced tremendous growth in recent years Includes contributions from leading researchers in the field Shows how this new catalysis combines the selective recognition/binding properties of enzymes with transition metal catalysts Written for catalytic chemists, bioinorganic chemists, biochemists, and organic chemists, Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a unique reference to the fundamentals, concepts, applications, and the most recent developments for more efficient and sustainable synthesis.
Download or read book Palladium Catalysis Directed Towards the Synthesis of Natural Products written by Lara Schwartz Kallander and published by . This book was released on 1998 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Total Synthesis of Plakortide E and Biomimetic Synthesis of Plakortone B written by Xiao-Yu Sun and published by Springer Science & Business Media. This book was released on 2012-01-15 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: In his thesis, Xiaoyu Sun conducts the first total synthesis of all possible stereoisomers of plakortide E and also confirms the absolute configuration of natural plakortide E. Xiaoyu Sun subsequently converts Plakortide E methyl ester to plakortone B in a biomimetic conversion. Construction and functionalization of cyclic peroxides are notoriously difficult due to the very low O-O bond dissociation energy. Plaktoride E is isolated from the Jamaican marine sponge platorits halichondrioides and contains a five-membered peroxide ring, with oxygen atoms linked to tertiary C4 and C6 centers. The methodology used for synthesizing highly substituted cyclic peroxides is novel and useful, and not only extends the field of Pd-catalyzed reactions, but also provides a convenient synthetic approach for the preparation of the 1,2-dioxolanes series. Plakortide E and plakortone B are bioactive, which means that the synthetic studies on them and their analogs are pivotal in drug discovery.
Download or read book Synthetic Access to the Picrotoxane Family of Natural Products Via the Palladium Catalyzed Cycloisomerization of 1 6 enynes and Related Degradation Studies written by Michael J. Krische and published by . This book was released on 1996 with total page 674 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Strategies for the Synthesis of Bioactive Natural and Unnatural Products Via Palladium Catalyzed Asymmetric Allylic Alkylation written by Weiping Tang and published by . This book was released on 2004 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of Pd catalyzed Reactions in the Total Synthsis of Oroidin derived Alkaloids written by Manojkumar R. Bhandari and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The oroidin family of marine natural products is a growing group of sponge-derived alkaloids which contain 2-aminoimidazole and pyrrolecarboxamide fragments as their signature features. Due to their structural diversity and biological activity, many groups are interested in the total synthesis of these natural products. It has been proposed that many of the alkaloids in this family are produced in nature simply by dimerization and/or cyclization of the simplest member, oroidin. In this dissertation we have attempted to explore these biosynthetic relationships to complete the total synthesis of several oridin-derived natural products. This dissertation consists of two parts. The first part describes the total synthesis of the nominal structure of nagelamide D and the development of approaches towards total synthesis of other congeners with the nagelamide family. The second part of this dissertation describes studies of intramolecular cyclization reactions of imidazolylpropargyl amides as linchpin synthons for the assembly of imidazole-containing natural products. In the first part, a Pd-catalyzed Stille reaction was used as a transformation to construct divinyl imidazole derivatives in convergent fashion. A divergent approach was used to further functionalize intermediates obtained from Stille reaction towards the total synthesis of several nagelamides. The total synthesis of nagelamide D was accomplished by using a double Mitsunobu reaction to install pyrrolecarboxamides. Selective hydrogenation of a trisubstituted olefin or electrocyclization reactions of divinyl intermediates obtained from the Stille reaction provided key frameworks required for the total synthesis of nagelamide A, nagelamide E and ageliferin respectively. Construction of the stereoisomeric Z-vinyl stannane provided access to the divinyl imidazole fragment required for the total synthesis of nagelamide C. In the second part, Pd-catalyzed and/or base promoted intramolecular cyclization reactions of imidazolylpropargyl amides were screened as a part of diversity oriented strategy for the assembly of natural product-like frameworks. Several novel heterocycles including morpholine, pyrazinone, oxazole, pyridinone and azepin derivatives were prepared using intramolecular cyclization. Many of these heterocyclic compounds have potential to serve as intermediates en route to the total synthesis of oroidin-derived alkaloids including stevensine, nagelamide R, nagelamide T, oxocyclostylidol, agelastatin A. The potential of this approach was demonstrated in a formal total synthesis of cyclooroidin.
Download or read book Green Techniques for Organic Synthesis and Medicinal Chemistry written by Wei Zhang and published by John Wiley & Sons. This book was released on 2018-01-18 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt: An updated overview of the rapidly developing field of green techniques for organic synthesis and medicinal chemistry Green chemistry remains a high priority in modern organic synthesis and pharmaceutical R&D, with important environmental and economic implications. This book presents comprehensive coverage of green chemistry techniques for organic and medicinal chemistry applications, summarizing the available new technologies, analyzing each technique’s features and green chemistry characteristics, and providing examples to demonstrate applications for green organic synthesis and medicinal chemistry. The extensively revised edition of Green Techniques for Organic Synthesis and Medicinal Chemistry includes 7 entirely new chapters on topics including green chemistry and innovation, green chemistry metrics, green chemistry and biological drugs, and the business case for green chemistry in the generic pharmaceutical industry. It is divided into 4 parts. The first part introduces readers to the concepts of green chemistry and green engineering, global environmental regulations, green analytical chemistry, green solvents, and green chemistry metrics. The other three sections cover green catalysis, green synthetic techniques, and green techniques and strategies in the pharmaceutical industry. Includes more than 30% new and updated material—plus seven brand new chapters Edited by highly regarded experts in the field (Berkeley Cue is one of the fathers of Green Chemistry in Pharma) with backgrounds in academia and industry Brings together a team of international authors from academia, industry, government agencies, and consultancies (including John Warner, one of the founders of the field of Green Chemistry) Green Techniques for Organic Synthesis and Medicinal Chemistry, Second Edition is an essential resource on green chemistry technologies for academic researchers, R&D professionals, and students working in organic chemistry and medicinal chemistry.
Download or read book Total Synthesis of Natural Products the Chiron Approach written by Stephen Hanessian and published by Pergamon. This book was released on 1983 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Application of Pericyclic Photolytic Chemoenzymatic and Cross coupling Techniques to the Synthesis of Biologically Active Natural Products and Related Structures written by Qiao Yan and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The body of this thesis is comprised of four scientific articles and is preceded by an overview that contextualises all of this submitted/published work. The first major part of this thesis is comprised of Publication 1. This details work concerned with establishing the true structure of the sorbicillinoid-derived isolate rezishanone C by total synthesis. Specifically, the enantiomer of what proved to be the true structure of the sorbicillinoid rezishanone C (sorbivinetone) was synthesized from the homochiral cis-1,2-dihydrocatechol that is itself generated through the whole-cell biotransformation of toluene. These studies and dispersion-corrected DFT calculations support the proposal that rezishanone C is an artefact of the isolation process and arises through a Diels-Alder cycloaddition reaction between ethyl vinyl ether and sorbicillinol. The second major part of the thesis is comprised of Publication 2. This is concerned with the synthesis and photochemical rearrangements of enantiomerically pure, polysubstituted and, in some cases, variously annulated bicyclo[2.2.2]octenones. Specifically, then, a series of bicyclo[2.2.2]octenones has been prepared by engaging the enzymatically-derived and enantiomerically pure cis-1,2-dihydrocatechol in either inter- or intra-molecular Diels-Alder cycloaddition reactions with various dienophiles. These polycyclic adducts or simple derivatives thereof were shown to readily participate in both photochemically promoted 1,3-acyl migration and oxa-di-pi-methane rearrangement processes to give corresponding products. The third major part of the thesis is comprised of Publication 3. This details the establishment of a palladium-catalyzed Ullmann cross-coupling/reductive cyclization route to the carbazole natural products 3-methyl-9H-carbazole, glycoborine, glycozoline, clausazoline K, mukonine and karapinchamine A. These were prepared by reductive cyclisation of the relevant 2-arylcyclohex-2-en-1-one to the corresponding tetrahydrocarbazole and dehydrogenation of this to give the target carbazole. Compounds of 2-arylcyclohex-2-en-1-one were themselves prepared using a palladium-catalyzed Ullmann cross-coupling reaction that served to link the appropriate 2-iodocyclohex-2-en-1-one and o-halonitrobenzene. The fourth and final part of the thesis is comprised of Publication 4. This details a unified approach to the isomeric alpha-, beta-, gamma- and delta-carbolines via their 6,7,8,9-tetrahydro counterparts. Specifically, then, a cross-coupling/reductive cyclisation protocol has been employed in preparing all four carbolines. So, for example, the 2-nitropyridine derivative, which is readily generated through an efficient palladium-catalyzed Ullmann cross-coupling reaction, is reductively cyclized under conventional conditions to give 6,7,8,9-tetrahydro-alpha-carboline that is itself readily aromatized to give alpha-carboline.
Download or read book Asymmetric Synthesis of Bioactive Lactones and the Development of a Catalytic Asymmetric Synthesis of Aryl Ketones written by Robert Doran and published by Springer. This book was released on 2016-10-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis addresses two fundamental areas in contemporary organic chemistry: synthesis of natural products and catalytic asymmetric synthesis. Firstly, a new methodology, developed by our research group, which allows the asymmetric synthesis of lactones, a structural unit ubiquitous in natural products, was utilised in the synthesis of a number of natural product analogues that showed significant biological activity. Secondly, the development of a catalytic asymmetric synthesis of a key structural motif present in a number of natural products and pharmaceuticals was accomplished. During the course of this work we discovered dual stereo control, which is significant because it allows the configuration of a new stereo centre to be controlled by a simple change of proton source.
Download or read book Strategies and Tactics in Organic Synthesis written by Michael F. Greaney and published by Elsevier Inc. Chapters. This book was released on 2013-07-29 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: This chapter describes the synthesis of two related sesquiterpenes, anislactone A and merrilactone A. We initially accessed a tetracyclic oxetane in the merrilactone series using a Paternò–Büchi reaction but found the compound to be too underfunctionalized to advance further. We then developed an approach based on reductive epoxide ring opening, whereby a fully elaborated C-ring epoxy-cyclopentane, containing five stereocenters, could undergo reductive epoxide cleavage when treated with Ti(III). The resulting tertiary radical then participates in a 5-exo-dig cyclization onto a pendant alkyne to afford the complete carbon skeleton of both natural products. From this point, orthogonal functionalization routes enabled the synthesis of both anislactone A and merrilactone A. A second-generation merrilactone A synthesis is then described, growing out of discoveries made over the course of the first route in the area of cyclopentannulation. An iodo-aldol method was used to develop an approach to the anislactone skeleton and succeeded in producing the BC bicycle with good stereocontrol and functional group tolerance. Further functionalization, however, did not prove possible due to excessive steric hindrance around the incorporated iodo group preventing any productive transformation. This problem was solved by switching the nucleophile in the tandem-aldol process to cyanide. The resulting domino cyanide-addition aldol cyclization was then successfully employed in the formal synthesis of merrilactone A, using a late-stage [2+2] photocycloaddition to access the D-ring.
Download or read book Palladium Catalysis for Natural Product Synthesis written by Matthew J. Durbin and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis details investigations towards the total synthesis of the naturally occurring alkaloid hodgkinsine, utilising palladium catalysis to achieve desymmetrisation of a meso-chimonanthine derivative. Initially, a Suzuki cross-coupling approach was envisaged. Meso-chimonanthine is functionalised as its C-7 bisiodide derivative by directed ortho-lithiation. Suitable electrophiles are screened for the successful preparation of additional bisbromide and bistriflate derivatives to broaden the scope of the cross-coupling. The synthesis of a suitable indole-3-boronic ester coupling partner is also achieved. Investigations into the post-Suzuki coupling elaboration of the indole moiety were conducted with model substrates to assess the viability of a proposed alkylation-cyclisation procedure. C-3 alkylation of various N-protected C-3 phenylindole derivatives was unsuccessful when employing aziridines, sulfamidites and sulfamidates as electrophilic two carbon fragments. Therefore a second generation boronic ester with latent enolate functionality for increased nucleophilicity was prepared in six high yielding steps from oxindole, via trapping 3-bromo-N-BOC-oxindole as the TIPS enol ether and subsequent C-3 palladium catalysed borylation. The Suzuki coupling of the new boronic ester with meso-chimonanthine derivatives was shown to be unsuccessful in a broad range of anhydrous and aqueous solvent systems. Palladium catalysts, ligands, bases and measures to reduce steric interactions were all screened in an attempt to achieve coupling. Subsequently the palladium catalysed arylation of N-protected oxindole enolates is developed; aryl bromides, chlorides and triflates are all suitable coupling partners, whilst a broad range of ortho, meta and para functionalised arenes are well tolerated providing C-3 aryl oxindoles in high yield. Extension of this methodology to a C-7 bisbromo meso-chimonanthine substrate was successful, furnishing the desymmetrised product under racemic conditions in 45% yield with the dicoupled product also observed in 20% yield.
Download or read book The Chemistry of Mycotoxins written by Stefan Bräse and published by Springer Science & Business Media. This book was released on 2013-02-14 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: The biological activity of mycotoxins ranges from weak and/or sometimes positive effects, such as antibacterial activity (see penicillin derivatives derived from Penicillium strains) to strong mutagenic (e. g. aflatoxins, patulin), carcinogenic (e. g. aflatoxins), teratogenic, neurotoxic (e. g. ochratoxins), nephrotoxic (e. g. fumonisins, citrinin), hepatotoxic, and immunotoxic (e. g. ochratoxins, diketopiperazines) activity. Nowadays, many laboratories around the world are specialized in the detection of mycotoxins in food products and contaminated material found in housing. In this volume, a focus on the most important classes of mycotoxins is provided and their chemistry of the last ten years is discussed. In each Section, the individual biological impact is outlined. Sections are arranged according to mycotoxin classes (e. g. aflatoxins) and/or structural classes (e. g. resorcinyl lactones, diketopiperazines). The biology of mycotoxins is also described.
Download or read book New Methods for the Synthesis of Biologically Active Natural Products written by Jeremy Nugent and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis consists of seven scientific articles and is preceded by an overview that contextualises all of this submitted/published work. Publication 1 is a literature review on the chemistry of the palladium-catalysed intramolecular Alder-ene (IMAE) reaction, a powerful method for the construction of carbon-carbon bonds. It focusses only on the cyclisation reactions of hetero-atom linked 1,6-enynes to form cis-fused hexahydro-indoles and -benzofurans. It serves to contextualise some of the author's other published research in the area. Publication 2 consists of an invited book chapter that reviews the Banwell Group's efforts to synthesis the Amaryllidaceae alkaloid galanthamine, as well as analogues thereof, in order to further investigate the biological properties of such compounds. Similarly, Publication 3 reports a seventeen-step reaction sequence that was used to synthesise rac-galanthamine. This route featured an intramolecular Alder-ene cyclisation and a Diels-Alder/aromatisation reaction sequence to install the tricyclic framework of the natural product. Publication 4 describes the first total synthesis of the Illicium-derived sesquineolignan simonsol C, a natural product that is structurally similar to galanthamine. This twelve-step synthesis of simonsol C featured a Mitsunobu reaction and an intramolecular Heck reaction to establish the tetracyclic framework of simonsol C. A second-generation synthesis of rac-galanthamine is reported in Publication 5. This investigation, which used methodology developed in the aforementioned synthesis of simonsol C, involved, as a key step, an intramolecular Heck reaction to install the tricyclic framework of rac-galanthamine. Publication 6 describes investigations concerned with establishing the reactivity profile of N-methoxy-N-methylcyanoformamide and its capacity to introduce the Weinreb amide functionality into organic frameworks. Specifically, it describes the reaction of this cyanoformamide with various enolates and organometallic species. Publication 7 details the synthesis of N-methoxy-N-methylcyanoformamide (a previously unreported compound) via a two-step procedure. The Appendix to the thesis is comprised of a report arising from single-crystal X-ray analysis of a key compound synthesized by the author. This analysis and the derived reports are the result of studies carried out by Dr Brett Schwartz.
