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Showing 1 to 20 of 26 for “"Thioesters"”.
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Chemical Synthesis Of Peptides And Peptide Thioesters
… for the block synthesis of peptides and peptidyl thioesters. A direct approach for the Fmoc-SPPS of peptidyl thioesters is also delineated in this thesis.</p> <p>In the first part of chapter one, the difficulty and importance of chemical synthesis of peptides is explained, and a brief survey of …
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Synthetically Useful Dipole-Stabilized Carbanions From Thioesters and Thiocarbamates
… formation of dipole-stabilized carbanions from thioesters, deprotonation of a tertiary center at the carbon adjacent to the sulfur of a thioester was found for the first time. Isopropyl, 2-octyl, and 4-tert-butylcyclohexyl 2,4,6-triisopropylthiobenzoates react with sec-butyllithium/TMEDA at …
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Acyclic Imidate and Thiomidate Normal-Oxides: Nitrones of Esters and Thioesters (alpha-Alkoxynitrones, Alpha-Alkylthionitrones, Normal - Alkylthiohydroxamic Acids, X-Ray)
Two N,O-dialkylacetimidate N-oxides and their hydrochlorides, and the hydrochloride of O-ethyl-N-methylpropionimidate N-oxide were prepared in dichloromethane solutions by the acid-catalyzed condensation of N-alkylhydroxylamines with aliphatic orthoesters. The (alpha)-alkoxynitrones and their …
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New Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D
<p>Cascade reactions, also referred to as domino reactions, have been widely used for the formation of carbon-carbon bonds. This type of reaction has the potential to circumvent protection and deprotection steps, shortening an overall synthetic process.</p><p>The Morita-Baylis-Hillman (MBH) …
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Ferrocenic metal chelators : synthesis, biological and electrochemical studies
… parasite. The intermediate thiosemicarbazone thioesters were also tested against different malaria parasite including chloroquine resistant (K1) and chloroquine sensitive (307) strains as well as against the causative agent of African trypanosomiasis, Trypanosoma brucei (T. brucei). Of the …
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Palladium-katalysierte enantioselektive Synthese allylischer Thiocarboxylate und Palladium-katalysierte Deracemisierung allylischer Carbonate
… ligand. By this method the corresponding allylic thioesters could be achieved with high ee values and yields. The reaction of the acyclic allylic carbonates with KSAc and KSBz afforded the E- and the Z-Isomers of the thioesters. Using cyclic allylic carbonates as substrates the formation of the …
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Development of New Organic Photoredox Catalysis Driven by Visible Light
… method for preparing structurally diverse thioesters from readily accessible, abundant aldehydes, has been realized. Excited by blue light, the simple and cost-effective 9,10-phenanthrenequinone (PQ) promotes hydrogen atom transfer (HAT) to selectively generate acyl radicals from …
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Development And Applications Of Thioacids In Peptide Chemistry And Exploration Of Methods Toward The Stereochemical Elucidation And Synthesis Of Virgineone
… for the synthesis of peptidyl thioacids and thioesters, with particular emphasis on applications in peptide chemistry, and the exploration of methods toward the assignment of the relative and absolute configuration of virgineone and its total synthesis.</p> <p>The first part of chapter one …
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The Polymerisation of Sulphur containing Heterocycles
… and the reaction products (principally poly-a-thioesters) characterised. The characteristics of the reactions of the α-thioacidanhydrocarboxylates with protic and with aprotic bases are quite different. Mechanisms have been proposed that account for these differences and for the observed …
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Charakterisierung von Acyl-CoA-Reduktasen
… catalyze a NADPH dependent reduction of acyl-CoA thioesters to fatty alcohols. Two groups of isozymes with different properties were identified, termed FAR1 and FAR2. The FAR1 group mainly synthesized 1-hexadecanol, whereas the FAR2 group preferred stearoyl-CoA as substrate. Semi-quantitative …
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Acyltransferase LovD as a Simvastatin Synthase: Mutational Deconvolution, Design, Substrate Scope and Immobilization
… esters as efficient alternatives to thioesters as acyl donor agents is described. Finally, the immobilization of a designed LovD variant on different solid supports with different characteristics is accomplished, and the properties of the resulting biocatalysts are analyzed in detail …
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CHIRAL LEWIS BASES ACTIVATION OF TRICHLOROSILYL DERIVATIVES
… direct aldol reaction of ketones and activated thioesters to aromatic aldehydes. β-hydroxy-ketones have been obtained with good anti diastereoselecitivity (up to 86%) and excellent enantioselectivity for the major anti isomer (up to 95%). By the same procedure β-hydroxy trifluoroethylthioester …
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1. C-C Bond Formation via Soft Enolization and Umpolung-like Chemistry 2. Electrophilic Fluorination of Organozinc Reagents
… The direct synthesis of 1,3-diketones and β-keto thioesters using in good yields and with wide substrate tolerance was possible using our soft enolization strategy using crude acyl chlorides. Another C-C bond strategy explored was an Umpolung-like approach towards α-functionalization of ketones. …
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Solid-supported synthesis of peptidoglycan fragments and their biological evaluation
… of the specific affinity for the R enantiomer of thioesters, the enantioselective synthesis of (R)-S2d is described that makes use of the coupling agent T3P. A chromatographic method is proposed to evaluate the degree of thioester racemization. The kinetics of the interaction between the thioester …
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Mechanistic Studies of the Activation of Ubiquitin-Conjugating Enzymes by Ring-Type Ubiquitin Ligases
… cannot be stimulated to release their ubiquitin thioesters in the presence of an E3 enzyme. We also show that thioester release measurements agree with polyubiquitination of physiological targets. We have structurally characterized our model E2 enzyme UbcH5b, it mutants, and its interaction with …
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Chemical Modification Methods for Protein Misfolding Studies
… the synthesis of thioamide-containing peptide thioesters as NCL substrates, and demonstrated their applications in generating a thioamide/Trp-dually labeled α-synuclein (αS), which was subsequently used in a proof-of-concept misfolding study. To remove the constraint of a Cys at the ligation …
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Investigation of artificial malonyl group carriers and multifunctional cyclic scaffolds towards the mimicry of PKS
… the synthesis of malonic acid half esters and thioesters under solvent-free conditions. The relative acidity of a broad variety of MAHOs and MAHTs has been estimated by an innovative and simple method based on the determination of observed rate constants from hydrogen-deuterium exchange …
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Mechanisms of Non-Enzymatic Peptide Bond Formation: Thioester and Transamidation Routes
… of phenylalanine peptides and peptidyl thioesters, and the spontaneous cyclization of glutamine t-butyl ester (Gln-tbe) into pyroglutamic acid t-butyl ester. Internal standard-based quantitative MS determined that 4.9 x 10-5 sec-1 was the rate constant for spontaneous Gln-tbe cyclization …
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Spectroscopic and functional models for Hmd hydrogenase
… to be a suitable alternative. The addition of thioesters, derived from the reaction of o-diphenylphosphino benzoic acid with a multitude of thiols, to Fe(0) carbonyls resulted in oxidative addition of the thioester to give complexes of the type Fe(SR)(Ph2PC6H4CO)(CO)3 with a chelating phosphine …
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