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Showing 1 to 20 of 28 for “"aziridines"”.
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Organocatalytic synthesis of chiral non-racemic aziridines, labelled with 2H, 15N, 13C stable isotopes
Aziridines are ‘keystone’ synthetic building blocks - relatively reactive, three-membered heterocycles with the potential for generating ‘secondary’ high value entities such as α- or β-amino acids via ring-opening reactions. Within this thesis, a one-pot asymmetric organocatalytic methodology is …
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Remote asymmetric induction in the organocatalytic azaDarzens synthesis of peptide aziridines: towards the assembly of new glycopeptide antibiotic analogues
… A structurally diverse range of peptide aziridines are reported in yields and diastereoselectivity of up to 99%. It is anticipated that the remote asymmetric induction methodology described in this thesis will be applicable not only to the synthesis of novel glycopeptide antibiotics and …
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Studies towards the Organocatalytic ‘Dialled In’ Synthesis of Chiral, Non-Racemic Aziridines, and Amino Acids, Containing Multiple Isotopic Labels
… % isotopic enrichment. Further to this, these aziridines have been submitted to ring opening methodologies in order to produce enantiomerically enriched a-amino acid derivatives bearing regioselectively introduced deuterium labels (with generally >90 % isotopic enrichment), in yields of up to …
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FREE-BASE PORPHYRIN FOR CO2 ACTIVATION
… the analogous carbon dioxide cycloaddition to aziridines has been much less studied and the conversion of N aryl aziridines into corresponding oxazolidinones resulted challenging and only few examples of efficient catalysts have been reported up to now. This work is devoted to the study of …
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New applications of Imidazotetrazinone prodrugs. Synthesis and mechanistic investigation of novel imidazotetrazinones as prodrugs of aziridines and as traceless carriers for drug delivery to the central nervous system.
New imidazotetrazinones have been synthesised that possess features in their structures to release aziridinium ions upon ring opening. Unstable 2-aminoethylisocyanates were required in this preparation, which were synthesized with BOC-protection of the amino group to counteract the reactivity of …
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Gold-catalysed reactions of Nitrogen containing molecules
… pyrroles by the cycloisomerisation of alkynyl aziridines, and the formation of α,β-unsaturated imides by the oxidation of ynamides has been developed. A rare gold-mediated vinylidene rearrangement of brominated or silylated alkynes has been used to prepare brominated or silylated …
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Developments and applications of methods for palladium- and copper-catalyzed carbon-nitrogen bond formation
… CuH catalysis to the synthesis of chiral N-alkyl aziridines (Chapter 2), and the discovery and development of novel electrophilic amines to enable CuH-catalyzed asymmetric hydroamination to directly access primary amines (Chapter 3). Part I. Chapter 1. Use of a "Catalytic" Cosolvent, N,N-Dimethyl …
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The Asymmetric Total Synthesis of Cephalotaxine
… rearrangement of 1-vinyl-2-aryl-aziridines, has been developed and applied to the synthesis of the Cephalotaxus alkaloids. The synthetic approach begins with D-ribose and utilizes the [3,3] sigmatropic rearrangement of a highly functionalized 1-vinyl-2-aryl aziridine and a …
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Asymmetric synthesis involving silicon
… trimethylsilyl amino alcohols and aziridines have been isolated by a multi-stage chirality transfer from their precursor diol involving no racemization. The main routes for these chirality transfers were via silylated cyclic sulphite or sulphate intermediates and via silylated …
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Synthesis of multicyclic ring systems including an alternate route to Meyers’ lactam derivatives
… towards the studies in formation of bicyclic aziridines; differing from current syntheses that require long reaction times and employing high temperatures. This project will aim to focus on the ability of catalytic quantities of Au(I) and or Au(III) to mediate the synthesis of 1-aza-bicyclo …
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TOWARDS SUSTAINABLE CATALYSIS: DESIGN OF EARTH-ABUNDANT METAL COMPLEXES FOR WASTE VALORIZATION
… Cycloaddition of carbon dioxide to epoxides and aziridines with metallATE catalysts. Synthesis and exploiting of the activity of different tetrabutylammonium tetrahalogeno metallate catalysts. Deep mechanistic study of the reaction of styrene oxide and carbon dioxide catalyzed by [TBA][FeCl3Br] …
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Asymmetric synthesis of benzylic and heterobenzylic amines
… carbonate. Asymmetric synthesis of 2-(2-pyridyl)aziridines from chiral 2-pyridineimines bearing a stereogenic center at the nitrogen atom was development. The envisioned route involves the addition of chloromethyllithium to the imine derived from 2-pyridinealdehyde and (S)-valinol, protected as …
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Asymmetric Dihydroxylation and Aziridination of Allenes and Related Chemistry
… and allene substitution are also discussed. Aziridines were formed by copper-catalyzed intramolecular nitrene addition to alkenes. The carbamate group was used as the tether between the alkene and the nitrene. Subsequent nucleophilic attack of the aziridine was accomplished using RSH, R2NH, …
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Curiosities of the Electron Dynamics of Spin-Crossover Solids (Moessbauer)
… derived from salicylalaldehyde and N-(aminoalkyl)aziridines have been prepared and their spin-crossover properties in the solid state have been characterized using variable-temperature (4.2-313 K) magnetic susceptibility, EPR spectroscopy, and ('57)Fe Mossbauer spectroscopy. For the unperturbed …
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SUSTAINABLE CATALYSIS VIA IRON AND ZINC COMPLEXES: FROM TUNABLE METALLATE SYSTEMS TO PHOTOCHEMICAL REACTIVITY
… for the cycloaddition of carbon dioxide to aziridines and epoxides, yielding oxazolidinones and cyclic carbonates, respectively. These catalysts operate through a dynamic equilibrium between a neutral metal halide acting as a Lewis acid and free halide anions acting as nucleophiles. …
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Development of new synthetic methodologies
… diamine derivatives have been converted into aziridines and a,p-differentiated amino acids. Baylis-Hillman type adducts are obtained by the treatment of aldehydes with acetylenic carbonyl compounds in the presence of TiCI4 as the Lewis acid promoter. The reaction proceeds through the formation …
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Desymmetrilizing Organic Molecules via Structural Functionalization
… include organocatalytic desymmetrization of meso-aziridines, desymmetrization of meso-glutaric anhydrides catalyzed by Ni2-Schiff bases, asymmetric amination of selected prochiral ketones, selective diester hydrolysis, selective oxidation of diols and triol, etc. This master thesis will be mainly …
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