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Enantioselective Total Synthesis Of The Agelastatin And Trigonoliimine Alkaloids
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Book Synopsis Enantioselective Total Synthesis of the Agelastatin and Trigonoliimine Alkaloids by : Sunkyu Han
Download or read book Enantioselective Total Synthesis of the Agelastatin and Trigonoliimine Alkaloids written by Sunkyu Han and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: I. Total Synthesis of the (-)-Agelastatin Alkaloids The pyrrole-imidazole family of marine alkaloids, derived from linear clathrodin-like precursors, constitutes a diverse array of structurally complex natural products. The bioactive agelastatins are members of this family that possess a tetracyclic molecular framework incorporating C4-C8 and C7-N12 bond connectivities. We provide a hypothesis for the formation of the unique agelastatin architecture that maximally exploits the intrinsic chemistry of plausible biosynthetic precursors. We report the concise enantioselective total syntheses of all known agelastatin alkaloids including the first total syntheses of agelastatins C, D, E, and F. Our gram-scale chemical synthesis of agelastatin A was inspired by our hypothesis for the biogenesis of the cyclopentane C-ring and required the development of new transformations including an imidazolone-forming annulation reaction and a carbohydroxylative trapping of imidazolones. II. Total Synthesis of the (-)-Trigonoliimine Alkaloids The concise and enantioselective total syntheses of (-)-trigonoliimines A, B, and C are described. Our unified strategy to all three natural products is based on asymmetric oxidation and reorganization of a single bistryptamine, a sequence of transformations with possible biogenetic relevance. We revise the absolute stereochemistry of (-)-trigonoliimines A, B, and C.
Book Synopsis Synthesis and Anticancer Evaluation of Agelastatin Alkaloid Derivatives and Enantioselective Total Synthesis of Aspidosperma Alkaloids by : Alyssa Hope Antropow
Download or read book Synthesis and Anticancer Evaluation of Agelastatin Alkaloid Derivatives and Enantioselective Total Synthesis of Aspidosperma Alkaloids written by Alyssa Hope Antropow and published by . This book was released on 2018 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: I. Synthesis and Evaluation of Agelastatin Derivatives as Potent Modulators for Cancer Invasion and Metastasis The synthesis of new agelastatin alkaloid derivatives and their anticancer evaluation in the context of the breast cancer microenvironment is described. A variety of Ni -alkyl and C5-ether agelastatin derivatives were accessed via application of our strategy for convergent imidazolone synthesis. We have discovered that agelastatin alkaloids are potent modulators for cancer invasion and metastasis at non-cytotoxic doses. We discuss the increased potency of (-)-agelastatin E as compared to (-)-agelastatin A in this capacity, in addition to identification of new agelastatin derivatives with activity that is statistically equivalent to (-)-agelastatin E. II. Enantioselective Synthesis of (-)-Vallesine: Late-stage C17-Oxidation via Complex Indole Boronation The first enantioselective total synthesis of (-)-vallesine via a strategy that features a late-stage regioselective C17-oxidation followed by a highly stereoselective transannular cyclization is described. The versatility of this approach is highlighted by divergent synthesis of the archetypal alkaloid of this family, (+)-aspidospermidine, and an A-ring oxygenated derivative (+)- deacetylaspidospermine, the precursor to (-)-vallesine, from a common intermediate. III. Enantioselective Total Synthesis of (-)-Jerantinine A from (-)-Melodinine P via Bio-Inspired A-Ring Oxidation The first enantioselective synthesis of (-)-melodinine P and its direct conversion to related alkaloid (-)-jerantinine A is described. A key para-aza-quinone methide pentacyclic intermediate enables A-ring to C-ring oxidation state transfer. Our synthesis is streamlined through the development of two multi-step single-pot procedures which proceed with high efficiency. We further demonstrate the utility ofpara-aza-quinone methide intermediates in our strategy for CI6-methoxylation which provides entry to the (-)-jerantinine alkaloid family.
Book Synopsis Enantioselective Total Syntheses of Acylfulvene, Irofulven, and the Agelastatins by : Dustin Scott Siegel
Download or read book Enantioselective Total Syntheses of Acylfulvene, Irofulven, and the Agelastatins written by Dustin Scott Siegel and published by . This book was released on 2010 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: I. Enantioselective Total Synthesis of ( - )-Acylfulvene, and ( - )-Irofulven We report the enantioselective total synthesis of ( - )-acylfulvene and ( - )-irofulven, which features metathesis reactions for the rapid assembly of the molecular framework of these anti tumor agents. We discuss (1) the application of an Evans Cu-catalyzed aldol addition reaction using a strained cyclopropyl ketene thioacetal, (2) an efficient enyne ring-closing metathesis cascade reaction in a challenging setting, (3) the reagent, IPNBSH, for a late stage reductive allylic transposition reaction, and (4) the final ring-closing metathesis/dehydrogenation sequence for the formation of ( - )-acylfulvene and ( - )-irofulven. II. Total Synthesis of the ( - )-Agelastatin Alkaloids The pyrrole-imidazole super-family of marine alkaloids, derived from linear clathrodinlike precursors, constitutes a diverse array of structurally complex natural products. The bioactive agelastatins are members of this family that have a tetracyclic molecular framework incorporating C4-C8 and C7-N12 bond connectivities. We provide a hypothesis for the formation of the unique agelastatin architecture that maximally exploits the intrinsic chemistry of plausible biosynthetic precursors. We report the concise enantioselective total syntheses of the agelastatin alkaloids, including the first total syntheses of agelastatins C and E. Our gram-scale chemical synthesis of agelastatin A was inspired by our hypothesis for the biogenesis of the cyclopentane C-ring and required the development of new transformations including an imidazolone-forming annulation reaction and a carbohydroxylative trapping of imidazolones.
Book Synopsis Studies Toward the Enantioselective Total Synthesis of the Martinella Alkaloids by : Vivek Badarinarayana
Download or read book Studies Toward the Enantioselective Total Synthesis of the Martinella Alkaloids written by Vivek Badarinarayana and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation consists of two parts. The first part describes the enantioselective total synthesis of martinellic acid. The Martinella alkaloids have attracted considerable attention in the synthetic community over the past few years. This interest is due in large part to their unique structure and useful biological activity (bradykinin receptor antagonist). In model systems we have successfully used the [3+2] azomethine ylide-alkene cycloaddition to construct the heterocyclic core of these alkaloids. The enantioselective approach described herein also involves the azomethine ylide-alkene cycloaddition as a key step in the total synthesis. The pyrrolo[3,2-c]quinoline core of this alkaloid was constructed in an enantioselective fashion by the elaboration of an N-aryl pyrrolidinone, which was obtained via Pd-catalyzed aryl amination reaction using a non-racemic lactam. Pirkle's chiral solvating agent was successfully used to demonstrate the stereochemical integrity of not only the N-aryl lactam (obtained by Pd-catalyzed cross-coupling) but also the cycloaddition precursor and the cycloaddition product (tetracyclic pyrroloquinoline core). The tetracyclic compound obtained via the azomethine ylide-alkene cycloaddition was elaborated to ( - )-martinellic acid in 11 steps and 6% overall yield. The second part of this dissertation describes application of several novel organometallic complexes for carrying out various organic transformations. A fluorinated tris(pyrazolyl)borato silver(I) complex catalyzes the addition of ethyl diazoacetate to benzene rings, providing norcaradienes, which undergo electrocyclization to provide the corresponding cycloheptatriene (the Bu & huml;chner reaction). These reactions are surprisingly selective for addition to the aromatic moiety rather than C-H insertion. A copper complex containing a fluorinated triazapentadienyl ligand has been used to catalyze some carbene and nitrene addition and insertion chemistry. Nitrene addition occurs rapidly and with both aryl and alkyl substituted olefins providing the corresponding aziridine. The carbene transfer reactions that were attempted include C-H insertion, O-H insertion and N-H insertion, of which the latter two were very efficient.
Book Synopsis Studies Directed Toward the Enantioselective Total Synthesis of Guattegaumerine by : Cheryl Faye Lichti
Download or read book Studies Directed Toward the Enantioselective Total Synthesis of Guattegaumerine written by Cheryl Faye Lichti and published by . This book was released on 1993 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enantioselective Total Synthesis of Galbulimima Alkaloids GB13 and Himgaline by : Unmesh Shah
Download or read book Enantioselective Total Synthesis of Galbulimima Alkaloids GB13 and Himgaline written by Unmesh Shah and published by . This book was released on 2006 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enantioselective Total Synthesis of Shahamin K and Enantioselective Total Synthesis of Quadrigemine C, and Psycholeine by : Alec Donald Lebsack
Download or read book Enantioselective Total Synthesis of Shahamin K and Enantioselective Total Synthesis of Quadrigemine C, and Psycholeine written by Alec Donald Lebsack and published by . This book was released on 2002 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enantioselective Total Synthesis of (+)-arborescidine C and Related Tetracyclic Indole Alkaloids Using Organocatalysis by : 賽思
Download or read book Enantioselective Total Synthesis of (+)-arborescidine C and Related Tetracyclic Indole Alkaloids Using Organocatalysis written by 賽思 and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Catalytic Enantioselective Total Synthesis of Picrotoxane Alkaloids and Guaiane Sesquiterpene Englerins A and B by : Lei Guo
Download or read book Catalytic Enantioselective Total Synthesis of Picrotoxane Alkaloids and Guaiane Sesquiterpene Englerins A and B written by Lei Guo and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enantioselective Total Syntheses of Akuammiline Alkaloids and Arynes as Building Blocks for Enantioenriched Products by : Elias Picazo
Download or read book Enantioselective Total Syntheses of Akuammiline Alkaloids and Arynes as Building Blocks for Enantioenriched Products written by Elias Picazo and published by . This book was released on 2018 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation features two projects concerning natural product synthesis and reaction development. The importance of natural product synthesis in chemistry and medicine cannot be overstated. In addition to providing a complex setting to test and apply new synthetic methodologies, natural products play a vital role in public health. Their influence in the pharmaceutical industry is profound, as approximately half of all chemical entities to treat disease come from natural product mimics, derivatives, or natural products themselves. With new natural products being discovered daily, there exists an ongoing need to develop efficient syntheses of these compounds and their derivatives. Chapters One, Two, Three, and Four focus on an unusual variant of the Fischer indolization reaction and its application in the total synthesis of a particularly interesting class of indole alkaloids named the akuammilines. Specifically, Chapter One provides an overview of the so-called 'interrupted Fischer indolization reaction'. This reaction is described from a methodological standpoint and is then evaluated in the context of akuammiline alkaloid total synthesis. Chapters Two, Three, and Four describe enantioselective syntheses of various akuammiline alkaloids, in addition to several akuammiline alkaloid derivatives. Central to our approach was the development of modern variants of the classic Fischer indolization reaction to generate high levels of complexity. These efforts culminated in the first enantioselective total syntheses of (-)-aspidophylline A, (+)-strictamine, (-)-2(S)-cathafoline, (-)-pseudoakuammigine, (+)-akuammiline, (-)-10-demethoxyvincorine, and derivatives therein. Chapters Five describes an application of the distortion/interaction model to a variety of mono and disubstituted benzynes and substituted indolynes. Chapter Six is focused on the development of a facile method to synthesize stereodefined quaternary centers from reactions of arynes and related strained intermediates with b-ketoester-derived substrates. Our approach provides a general solution to the challenging problem of stereoselective b-ketoester arylation/alkenylation, with formation of a quaternary center with enantiomeric excess up to 96%.
Book Synopsis Further Progress Towards Enantioselective Total Synthesis of the Bisbenzyltetrahydroisoquinoline Alkaloid ( - )-cycleanine by : Ningzhang Zhou
Download or read book Further Progress Towards Enantioselective Total Synthesis of the Bisbenzyltetrahydroisoquinoline Alkaloid ( - )-cycleanine written by Ningzhang Zhou and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Progress Towards Enantioselective Total Synthesis of the Bisbenzyltetrahydroisoquinoline Alkaloid ( - )- Cycleanine and a New Approach to the Syntheses of Some Isoquinolones by : Jianwen Cui
Download or read book Progress Towards Enantioselective Total Synthesis of the Bisbenzyltetrahydroisoquinoline Alkaloid ( - )- Cycleanine and a New Approach to the Syntheses of Some Isoquinolones written by Jianwen Cui and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies Directed Towards the Enantioselective Total Synthesis of Trans-Dihydrolycorcidine by : William L. Brown
Download or read book Studies Directed Towards the Enantioselective Total Synthesis of Trans-Dihydrolycorcidine written by William L. Brown and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis First Total Synthesis of (+/- )- and ( - )-actinophyllic Acid and First Enantioselective Total Synthesis of Condylocarpine-type Alkaloids by : Connor L. Martin
Download or read book First Total Synthesis of (+/- )- and ( - )-actinophyllic Acid and First Enantioselective Total Synthesis of Condylocarpine-type Alkaloids written by Connor L. Martin and published by . This book was released on 2011 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1. The unique indole alkaloid ( - )-actinophyllic acid (1) is introduced. Its biological activity, structural relationship to other indole alkaloids, and potential biosynthesis are discussed. Our plan for synthesizing ( - )-actinophyllic acid with the use of the aza-Cope/Mannich reaction as a key step is described in detail. Chapter 2. The first-generation total synthesis of (±)-actinophyllic acid (rac-1) is described. The central step in this synthesis is the aza-Cope/Mannich reaction, which constructs the core of the previously unknown hexacyclic ring system of actinophyllic acid from a much simpler tetracyclic precursor. The hexahydro-1,5-methano-1H-azocino[4,3-b]indole ketone rac-121 is assembled from o-nitrophenylacetic acid in four steps, with oxidative cyclization of the dienolate derivative of tricyclic precursor rac-119 being the pivotal step. In the most concise route, rac-121 is elaborated to allylic alcohol rac-130, which is transformed to pentacyclic ester rac-134 by a one-pot global deprotection-aza-Cope/Mannich-Fisher esterification sequence. In two additional steps, this intermediate is advanced to (±)-actinophyllic acid. Chapter 3. The second-generation total syntheses of (±)-actinophyllic acid (rac-1) and ( - )-actinophyllic acid (1) are described. The first-generation synthesis is streamlined by elaborating ketone rac-121 to B-hydroxyester intermediate rac-141, which is directly transformed to (±)-actinophyllic acid upon exposure to HCl and paraformaldehyde. This concise synthesis of (±)-actinophyllic acid is realized in 22% overall yield from commercially available di-tert-butyl malonate and o-nitrophenylacetic acid by a sequence that proceeds by way of only six isolated intermediates. The first enantioselective total synthesis of ( - )-actinophyllic acid (1) is accomplished by this direct sequence from tricyclic keto malonate (S)-119. Catalytic enantioselective reduction of enone 163 is the key step in the preparation of intermediate (S)-119 from the commercially available Boc-amino acid 161. Chapter 4. The first enantioselective total syntheses of indole alkaloids of the condylocarpine type are described. (+)-Condylocarpine (174a), (+)-isocondylocarpine (174b), and (+)-tubotaiwine (217) are prepared in high enantiomeric purity (>99% ee) from (1S,5R)-hexahydro-1,5-methano-1H-azocino[4,3-b]indole-12-one (1S,5R)-121 by way of five or six isolated intermediates.
Book Synopsis Enantioselective Syntheses of Alkaloids from & -amino Acids by : Robert Michael Henry
Download or read book Enantioselective Syntheses of Alkaloids from & -amino Acids written by Robert Michael Henry and published by . This book was released on 1997 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enantioselective Total Synthesis of the Antitumor Alkaloid (+)-pancratistatin and Ring Opening Olefin Metathesis of Cyclobutenes by : Umar S. M. Maharoof
Download or read book Enantioselective Total Synthesis of the Antitumor Alkaloid (+)-pancratistatin and Ring Opening Olefin Metathesis of Cyclobutenes written by Umar S. M. Maharoof and published by . This book was released on 1999 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies Directed Towards an Enantioselective Total Synthesis of the Marine Alkaloid Haouamine A by : Douglas R. Murken
Download or read book Studies Directed Towards an Enantioselective Total Synthesis of the Marine Alkaloid Haouamine A written by Douglas R. Murken and published by . This book was released on 2008 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
