Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 108 for “"Substrate Scope"”.
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Elucidating the Reactivity of Cytochrome P460: Maturation, Product Selectivity, and Substrate Scope
Ammonia oxidizing bacteria (AOB) have evolved a nitrogen-based metabolism in which they rely solely on the oxidation of ammonia as their energy for life. In contrast to carbon-based metabolisms, there is a large gap in our knowledge of nitrogen-based metabolisms. The primary energy producing step …
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Acyltransferase LovD as a Simvastatin Synthase: Mutational Deconvolution, Design, Substrate Scope and Immobilization
… and hydrolase activities, inhibition by substrate and thermal stability), is described, and new variants with fewer mutations and comparable catalytic activities are designed. Second, a rational design of native LovD is performed using computational methods for sequence diversification …
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Defining the substrate scope of DNAzyme catalysis for reductive amination with aliphatic amines
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-05-01
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Investigations of the Mechanism and Substrate Scope of the Enzymes Involved in Lantibiotic Biosynthesis
… five cysteine residues. This peptide is the substrate of the putative lantibiotic dehydratase, SpaB, and cyclase SpaC. The heterologously expressed and purified SpaS peptide was employed in assays with the purified SpaB and SpaC proteins to investigate conditions for the in vitro …
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Expanding the substrate scope in palladium-catalyzed C-N and C-C bond-forming reactions
… catalyst displayed unprecedented stability and scope allowing, for the first time, the coupling of substrates bearing a carboxylic acid or a primary amide.
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Studies on the Silanol-Based Cross-Coupling Reaction: (1) Development of Methods for the Synthesis of Aryl and Heteroaryldimethysilanols, (2) Expansion of the Substrate Scope of the Cross-Coupling Reaction and (3) Investigations on the Transmetalation of Organosilanols to Transition Metals
To further illuminate the mechanism of transmetalation of alkenyldimethylsilanols a number of molecular traps have been designed, synthesized and subjected to the cross-coupling reaction. A clear preference for formation of the cross-coupling products was observed in these investigations.
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Benign Catalysis and Expansion of Cyclobenzoins
… use of sodium cyanide as a catalyst or the small substrate scope, this thesis aims to improve on both limitations. The first issue, the cyanide catalyst, presented an opportunity to develop a new method to synthesize cyclotetrabenzoin. After testing a series of N-heterocyclic carbene catalysts, a …
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Development of Sustainable Catalytic Systems For Oxidation Reactions
… with nitric acid. The aim is to broaden the substrate scope of the reaction, whilst using a cheap, abundant source of NOx. Chapter three explores the use of Pd(II) catalysed oxidative carbonylation for the synthesis of 2-alkynoates. The focus is to use lower catalyst loadings than previously …
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The selective palladium-catalysed decarboxylative coupling of nucleophiles in the presence of propargylic electrophiles
… The reaction is applied to a wide range of substrates and forms two C–C bonds and installs two all-carbon quaternary centres. Mechanistic studies to help deduce the mechanism of the reaction are described, which shows that by utilising a propargyl enol carbonate as one of the coupling …
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OPPORTUNITIES AND CHALLENGES OF BIOCATALYSIS IN PHARMACEUTICAL SCIENCES: DEVELOPING TAILORED BIOCATALYSTS FOR SYNTHETIC APPLICATIONS
… as insufficient operational stability and narrow substrate scope, two complementary strategies were applied: enzyme immobilization and protein engineering. First, a biocatalytic cascade combining the ThDP-dependent enzyme Ao:DCPIP OR with stereoselective ATAs was established for the synthesis of …
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[3+2]-Cycloadditions of Azomethine Imines and Ynolates and Progress Towards a Radical Three-Component Cross-Coupling Reaction
… reactions, all of which have a severely limited substrate scope (e.g., only alkynes, one nucleophile, contains fluorine). Therefore, we envisioned a three-component radical cross-coupling reaction with a broad substrate scope encompassing multiple radical initiators and olefin acceptors. This …
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Ruthenium-Catalyzed Transformations for the Synthesis of Conjugated Dienes
… optimization, mechanistic hypothesis and substrate scope for the coupling with acrylates and vinyl boronates is described. The vinyl boronate scope and alkyne scope is presented, in addition to the selective derivatization of the boronate moiety. The synthesis of a chiral silicon-tethered …
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Studies Directed Toward the Synthesis of Streptonigrin
… offers both a way to test and showcase the true substrate scope of emerging synthetic methods; the pentasubstituted core of streptonigrin provides a window into the applications and limitations thereof.
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Nondirected C(sp2)–H Activation of (Hetero-)Arenes Through Ligand-Enabled Palladium Catalysis
… optimization was performed using a multi-substrate-screening approach, which allowed for the identification of optimal reaction conditions for different classes of heteroarenes from a minimal amount of screening reactions. Investigations of the substrate scope demonstrated the broad …
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Towards the automation of small molecule synthesis: The development of an impact-prioritized list couplings and blocks for building block assembly of most linear natural products
… coupling revealed a specific impact-prioritized substrate scope and functional group compatibility required to access this class of compounds. Because this analysis was not restricted to known chemistry, many of the identified couplings represent an actionable list of methodological problems that …
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The production and synthetic utility of the dioxygenase-derived metabolites of substituted aromatics
The substrate scope and selectivity of toluene dioxygenase overexpressed in E.coli JM109 (pDTG601A) was investigated with series of ortho-halobenzoates and para-substituted arenes. Palladium-catalyzed carbonylation methodology was developed to convert halogenated cis-dihydrodiol metabolites to the …
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Metal-free methodology for the preparation of ynones using potassium alkynyltrifluoroborates and its application to the synthesis of natural products
… air or water, is operationally simple, has broad substrate scope, and proceeds rapidly under mild conditions in the presence of a Lewis acid. 2,6-dimethoxy substituted anhydrides afford the corresponding mono-demethylated o-alkynoylphenol precursors of aurone and flavone natural product scaffolds …
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Deep Learning Multimodal Extraction of Reaction Data
… our system is able to infer structures in substrate scope diagrams as well as align reactions with their metadata defined elsewhere. In addition, we explore the chemistry information extraction potential of Vision Language Models (VLM), which allow powerful large language models to leverage …
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Mechanistic and synthetic studies on the prochlorosin and cytolysin families of lanthipeptides
… via Michael-type addition. The remarkably broad substrate scope of the synthetase ProcM inspired us to explore its mechanism in detail (chapter 2). My studies on ProcM revealed the directionality of dehydration, the order of cyclization, and that, despite the impressive substrate scope, none of …
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Metal-free C-H functionalisation methods
… through initial investigations, optimisation and substrate scope to mechanistic studies. Chapter 3 gives a detailed account of the development and mechanistic investigations of peroxide-mediated C–H functionalisation method exclusive to aromatic C–H bonds. Chapter 4 presents the experimental data …
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