Development of Multicomponent Assembly Processes and Their Application to the Synthesis of Novel Heterocyclic Scaffolds and the Total Synthesis of Actinophyllic Acid

Development of Multicomponent Assembly Processes and Their Application to the Synthesis of Novel Heterocyclic Scaffolds and the Total Synthesis of Actinophyllic Acid
Author: Brett Adam Granger
Publisher:
Total Pages: 908
Release: 2013
Genre:
ISBN:

Several novel multicomponent assembly processes have been developed for the preparation of a diverse array of complex heterocyclic systems from relatively simple starting materials. These studies resulted in the discovery of a new quinazolone forming reaction, which was applied to the one-step synthesis of the quinazolinocarboline alkaloid rutaecarpine. Biological screening of these complex heterocycles culminated in the identification of a potent sigma-2 receptor ligand. A novel N-acyliminium ion mediated cascade reaction was employed for the concise synthesis of (±)-actinophyllic acid. The completion of the synthesis relied on the development of a reaction sequence that avoided a potentially detrimental fragmentation process. Furthermore, several anti-cancer compounds were identified through a diverted total synthesis approach.

Handbook of Science & Engineering of Green Corrosion Inhibitors

Handbook of Science & Engineering of Green Corrosion Inhibitors
Author: Chandrabhan Verma
Publisher: Elsevier
Total Pages: 288
Release: 2021-11-19
Genre: Technology & Engineering
ISBN: 032390713X

Handbook of Science and Engineering of Green Corrosion Inhibitors: Modern Theory, Fundamentals and Practical Applications presents developments in green corrosion inhibitors and current applications. The book provides an overview of green corrosion inhibitors such as plant extracts, chemical medicines, natural polymers, synthetic green compounds, carbohydrates, amino acids and oleochemicals that can cost-effectively minimize corrosive damage. The book handles several compounds used as anticorrosive materials for different metals and alloys in a versatile corrosive environment. Sections address the fundamental characteristics of green corrosion inhibition and deal with the economic impact of corrosion and forms of corrosion, while also assessing and classifying corrosion inhibitors. The book covers a broad range of applications in green corrosion inhibition and concludes with new emerging trends in corrosion protection such as high temperature corrosion and its protection and nanomaterials as corrosion inhibitors. - Provides an overview of environmentally sustainable (green) corrosion inhibitors utilized in modern industrial platforms - Evaluates corrosion inhibitors as prime options for sustainable and transformational opportunities - Serves as a valuable reference for scientists and engineers who are searching modern design for corrosion inhibitors - Covers both synthetic and natural environmentally-friendly corrosion inhibitors

Synthesis of Bioactive Scaffolds

Synthesis of Bioactive Scaffolds
Author: Rakesh Kumar Sharma
Publisher: Walter de Gruyter GmbH & Co KG
Total Pages: 606
Release: 2022-08-22
Genre: Science
ISBN: 3110797461

Carbon-carbon and carbon-heteroatom bond-forming reactions are the backbone of synthetic organic chemistry. Scientists are constantly developing and improving these techniques in order to maximize the diversity of synthetically available molecules. These techniques must be developed in a sustainable manner in order to limit their environmental impact. This book highlights green bond forming reactions for bioactive scaffolds.

The Development of a Four Component Reaction and Its Application to the Synthesis of Diverse Heterocyclic Scaffolds and the Total Synthesis of Alkaloid Natural Products

The Development of a Four Component Reaction and Its Application to the Synthesis of Diverse Heterocyclic Scaffolds and the Total Synthesis of Alkaloid Natural Products
Author: James Dennis Sunderhaus
Publisher:
Total Pages: 868
Release: 2009
Genre:
ISBN:

A four component reaction involving the coupling of functionalized aldehydes, amines, acid chlorides, and [pi]- and organometallic nucleophiles has been developed to prepare multifunctional substrates that may be employed in subsequent ring-forming reactions to generate diverse arrays of functionalized heterocyclic scaffolds. Allyl metals, Grignard reagents, silyl ketene acetals, silyl enol ethers, and silyloxy furans have been utilized as the nucleophile in the four component reaction (4CR). The 4CR has been sequenced with intramolecular Heck reactions, Diels-Alder and (3+2) cycloadditions, ring closing metathesis (RCM), and Dieckmann condensations to provide a number of diverse heterocyclic structures. The practical utility of this approach to diversity-oriented synthesis (DOS) was further exemplified by its application to the first total synthesis of the isopavine alkaloid roelactamine, which was completed in only four steps from commercially available materials. The application of this methodology towards the synthesis of the Aspidosperma alkaloids rosicine and pseudotabersonine is also presented. To this end, an imine pentadienylation/double RCM strategy has been adopted to rapidly access the pentacyclic core of the aspidospermine alkaloids. This sequence involved the use of a pentadienyl aluminum reagent, which was found to react with aryl imines to give branched products in good yields.

Kinetic Control in Synthesis and Self-Assembly

Kinetic Control in Synthesis and Self-Assembly
Author: Munenori Numata
Publisher: Academic Press
Total Pages: 326
Release: 2018-11-23
Genre: Science
ISBN: 0128121270

Kinetic Control in Synthesis and Self-Assembly provides a unique overview of the fundamental principles, novel methods and practical applications for researchers across organic synthesis, supramolecular chemistry and materials sciences. The book examines naturally occurring molecular systems in which kinetic processes are more ubiquitous than thermodynamic processes, also exploring the control of reactions and molecular self-assemblies, through kinetic processes, in artificial systems. These methods currently play a crucial role for tuning materials functions. From organic synthesis, to supramolecular assemblies, and from restricted spaces, to material synthesis for hierarchical structures, the book offers valuable coverage for researchers across disciplines. Interesting topics include how to regulate kinetic pathways more precisely, essential molecular design for kinetic traps, and how molecular environments surrounding molecules (i.e., solvent, temperature, and pressure effects) influence kinetic control in reactions and self-assemblies. - Describes the nature and potential applications of kinetic processes compared to thermodynamic processes - Presents information useful to researchers active in molecular synthesis and self-assembly toward materials - Collates coverage of kinetic control for synthesis and self-assembly, treated separately in literature

Complexity-Generating Annulation Reactions in the Synthesis of Natural Products and Materials Scaffolds

Complexity-Generating Annulation Reactions in the Synthesis of Natural Products and Materials Scaffolds
Author: Robert Bergstrand Susick
Publisher:
Total Pages: 333
Release: 2020
Genre:
ISBN:

This dissertation encompasses several studies pertaining to natural product total synthesis, reaction methodology development, and organic materials. Given that natural product structures inspire the development of new agrochemicals and pharmaceuticals, their syntheses remain a worthwhile pursuit in organic chemistry. Furthermore, the successful completion of a total synthesis endeavor can confirm proposed molecular structures and biological activities, in addition to serving as a testing ground for new synthetic methods. Similarly, organic materials impact many areas of humanity, including technology, health, and energy conversion. Therefore, developing new reaction methodologies is crucial for expanding the architectures, and thereby properties, of organic materials. Specifically, photocatalysts and organic light-emitting diodes (OLEDs) often rely on photophysical properties imparted by N-containing polycyclic aromatic hydrocarbon (PAH) ligands. As such, new methods that provide access to unique N-containing heterocyclic scaffolds are highly desirable. Chapter one offers a current perspective on the field of natural product total synthesis. Although historically viewed as a highly competitive field, several recent syntheses demonstrate a growing spirit of collaboration in total synthesis. By forming alliances with chemists in other fields, industries, or laboratories, total synthesis chemists have made many breakthroughs that would arguably not have been possible if working independently. Chapter two describes our laboratory's total syntheses of several bioactive akuammiline alkaloids, including strictamine, 2(S)-cathafoline, akuammiline, -akuammigine, and 10-demethoxyvincorine. Our strategic approach to the natural products focused on the use of a modern variant of a classic reaction, the Fischer indolization, to install several rings and the common quaternary center found in each target. This strategy allowed for the first total syntheses of akuammilines bearing a methanoquinolizidine core, as well as those that bear vicinal quaternary centers. In addition, rearrangements of the methanoquinolizidine core were developed that allowed us to access pyrrolidinoindoline-containing akuammilines. Chapter three describes synthetic studies of the reactive intermediates 2,3-pyridyne and 4,5-pyrimidyne. Heterocycles bearing one or more nitrogen atom are privileged motifs in natural products and pharmaceuticals. Therefore, methodologies that decorate such heterocycles are of great interest to the synthetic and biological communities. Arynes are highly reactive, transient species that can efficiently build multiple bonds in a single transformation, and our lab is particularly interested in accessing new, heterocyclic arynes to study their reactivity. This study demonstrates the synthetic utility of 2,3-pyridyne and the undesired reactivity of a 4,5-pyrimidyne precursor. Chapter four describes synthetic studies toward the development of new methods to manipulate polypyridyl organometallic scaffolds. Ruthenium- and iridium-based polypyridyl organometallic complexes have been known for nearly a century and have broadly impacted the scientific community, including the areas of catalysis, bioimaging, and energy conversion. Despite decades of study, methods to synthesize polypyridyl ligands are limited to relatively few transformations, particularly when extending -conjugation. We detail the use of arynes to extend the conjugation of polypyridyl ligands "on-the-complex," thereby overcoming traditional limitations in ligand synthesis. We also disclose the first generation and trapping of a ligand-bound aryne on an organometallic complex. Chapter five describes the synthesis of a novel -extended carbazole ligand for the study of structure-property relationships in two-coordinate metal complexes. Recently, linear two-coordinate metal complexes of the general structure donor-metal-acceptor have been identified as promising dopants for OLEDs. Both the donor and acceptor ligand play a crucial role in tuning the photophysical properties of these complexes. However, donor ligands with extended -conjugation have not been studied in this context. Our approach leverages heterocyclic arynes to synthesize -extended donor ligands in a modular fashion, which can also apply to other PAHs. Subsequent photophysical studies of -extended two-coordinate metal complexes identify a new dopant that displays up to 80% photoluminescence efficiency.

Solid-Phase Synthesis

Solid-Phase Synthesis
Author: Fernando Albericio
Publisher: CRC Press
Total Pages: 849
Release: 2000-04-28
Genre: Medical
ISBN: 1482270307

This volume provides the information needed to synthesize peptides by solid-phase synthesis (SPS) - employing polymeric support (resins), anchoring linkages (handles), coupling reagents (activators), and protection schemes. It presents strategies for creating a wide variety of compounds for drug discovery and analyzes peptides, DNA, carbohydrates,

Molecular Technology, Volume 4

Molecular Technology, Volume 4
Author: Hisashi Yamamoto
Publisher: John Wiley & Sons
Total Pages: 428
Release: 2019-08-05
Genre: Science
ISBN: 3527345884

Edited by foremost leaders in chemical research together with a number of distinguished international authors, this fourth volume summarizes the most important and promising recent developments in synthesis, polymer chemistry and supramolecular chemistry. Interdisciplinary and application-oriented, this ready reference focuses on innovative methods, covering new developments in catalysis, synthesis, polymers and more.

Asymmetric Synthesis of Bioactive Lactones and the Development of a Catalytic Asymmetric Synthesis of α-Aryl Ketones

Asymmetric Synthesis of Bioactive Lactones and the Development of a Catalytic Asymmetric Synthesis of α-Aryl Ketones
Author: Robert Doran
Publisher: Springer
Total Pages: 0
Release: 2016-10-15
Genre: Science
ISBN: 9783319370347

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.

Total Synthesis of (-)-virginiamycin M2 and Chiral Organosilane Based Sequential Transformations to Access Polycyclic Scaffolds

Total Synthesis of (-)-virginiamycin M2 and Chiral Organosilane Based Sequential Transformations to Access Polycyclic Scaffolds
Author: Jie Wu
Publisher:
Total Pages: 834
Release: 2012
Genre:
ISBN:

Abstract: Research projects have involved the development of enantioenriched crotylsilane reagents and their application in natural product synthesis. These novel crotylsilanes were generated through Rh(II) or Cu(I) catalyzed asymmetric carbenoid Si-H insertion. Jacobsen's C2-symmetric copper(I) diimine complexes were applied to carbenoid Si-H insertions with a-diazovinylacetates, which resulted in the formation of crotylsilanes bearing C-centered chirality with high enantioenrichment. A comparison of chiral Cu(I) and Rh(II) catalysis was also detailed in this study. The generated organosilane products were then utilized in a Lewis acid-promoted crotylation with aldehydes and imines to provide stereochemically well-defined homoallylic ethers and carbamates. In some cases, [3 + 2] annulation products were formed through a [1,2]-silyl rearrangement pathway. (—)-Virginiamycin M2 belongs to a class of naturally occurring antibiotics known as virginiamycins. Derivatives of virginiamycins displayed potent antibiotic activity against methicillin-, erythromycin-, and vancomycin-resistant S. aureus. The unique chemical structure of (—)-virginiamycin M2 and its potential bioactivity motivated us to initiate a study towards its total synthesis. Notable features of our synthetic strategy included the application of the novel crotylsilane to address stereochemical features of the syn vinylogous aldol product; the use of an alkoxide-directed reductive coupling to assemble the ( E,E)-diene; and a SmI2-promoted Barbier-type macrocyclization to construct the 23-membered macrocycle. A sequential transformation involving an asymmetric crotylation followed by metal carbenoid reactions has been developed to access novel bicylic and tricyclic chemotypes. By subsequent pairing of installed functional groups using Heck cyclization or [2 + 2] photo-cycloaddition, the syntheses of tetracycles, pentacycles, and condensed polycycles were achieved with high stereochemical and skeletal variation. Densely functionalized chiral allylsilanes were accessed through organosilane based alkyne-alkene reductive coupling of readily available propargyl silanes. The chemodivergent reactivity of the generated allylsilanes was controlled with ease to deliver a broad range of novel carbocycles through the intramolecular allylation, [3 + 2] annulations, and a Sakurai-like homodimerization.