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 18 of 18 for “"quantitative yield"”.
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Alkene oxidation by platinum (II) oxo/hydroxo complexes
… (1) and norbornene (NB) yields the stable platinaoxetane [(COD)2Pt2(OC7H10)Cl][BF4] (2) in quantitative yield. A rapid reaction between NB and the novel (1,5-COD)Pt(II)-hydroxo complex [(COD)2Pt(OH)2]2+ (4) is observed and the protonated platinaoxetane [(COD)Pt(OH)C7H10)]+ …
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Applications of 2,3-Diketoesters in Organic Synthesis and Stereoselective Transformations
… diazoacetoacetates with aldehydes, occurred in quantitative yield to form dihydrofuranols that undergo acid catalyzed dehydration under mild conditions to generate 3-methoxyfuran-2-carboxylates in good yield. Oxidation of ζ-keto-α-diazo-β-ketoesters that are formed by zinc triflate catalyzed …
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Preparation of Pyridinium and Diaminocarbonium Barbituric Acid Ylides
… 1,3- dimethylbarbituric acid derivative with quantitative yields. An alternative approach was attempted in order to prepare chiral 5-ylide-pyridinium-methyl-barbituric acid derivatives thus containing a chiral center between the charge separation. The extreme instability of the derivatives …
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Photochemical Rearrangements of Tetraarylborate Salts: Direct Irradiation, Triplet Sensitization, and Single Electron Transfer
… of the borate and formation of biphenyl in quantitative yield.
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Gold-catalysed reactions of Nitrogen containing molecules
… synthesised in an atom-economical manner in near quantitative yield. From the same aryl-substituted starting materials the 2,4-substituted pyrrole isomer were accessed preferentially when a Ph\(_3\)PAuCl/AgOTf catalytic system was employed. A reaction mechanism accounting for the reaction outcome …
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Study of Nitrogenase Cofactors bound to Nitrogenase Carrier Proteins
… can be selectively labeled with ⁵⁷Fe in a near quantitative yield. Using this technology together with site-directed mutagenesis, we obtained the first concrete evidence that the L-cluster binds to the nitrogenase carrier protein NifX through His³⁵ residue. In addition, we extended the use of …
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ELECTROCHEMICAL ORGANIC TRANSFORMATIONS: FROM THE DEVELOPMENT OF ENANTIOSELECTIVE STRATEGIES TO CONTINUOUS-FLOW METHODOLOGIES
… that delivers α-chlorinated aldehydes in high yields and enantioselectivities (up to 97% ee). Translation to a continuous-flow electrochemical reactor enhances productivity and space-time yield, reducing residence times to less than two minutes while maintaining stereocontrol. Building on this …
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Functional Materials From Self-Assembled Macrocycles
… photo-cycloaddition reaction with a quantitative yield. Substitution of the urea group for a carbonate group afforded a macrocycle that displays similar photochemistry. The carbonate macrocycle is of particular interest due to the fact that it self-assembles into column through …
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Novel nitrogen containing polymers via Reissert chemistry
… These monomers were produced in high yields with preformed heterocyclic nuclei which included benzothiazole, isoquinoline and quinoline. Acylated linear polyamine derivatives were obtained by the step growth condensation polymerization of open chain bis(Reissert compound)s with …
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Derivatisierungsreaktionen von Cinchona-Alkaloiden und eine Cinchona-Alkaloid-katalysierte asymmetrische Synthese von 2,5-Diarylphopholanen
… able to synthesize various diarylbutadienes in yields of up to 75%. Submitted to a McCormack cycloaddition reaction, these butadienes reacted to give meso-2,5-diarylphosphol-3-enamides. The yield of the phosphacycles varied between 24 and 84%, depending on the steric hinderance of the aryl …
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Studies in stereoselective synthesis via reissert compound chemistry
… of the carbonate in pure form, hydrolysis yielded the enantiomerically pure (S)-(-)-1-isoquinoy] t-buty] carbinol (121). The proton NMR spectra of the diastereomeric Reissert compounds led to elucidation of the stereochemistry. The diastereomeric ratios were determined for both 110 and …
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PHOTOCHEMICAL AND TITANIUM (II) MEDIATED METHODS FOR THE SYNTHESIS OF COMPLEX MOLECULAR SCAFFOLDS
… (II) mediated Kulinkovich reaction traditionally yields cyclopropylamines and cyclopropanols from amides and esters, respectively. The reaction involves two consecutive carbon-carbon bond forming steps. The bridged tricyclic intermediates would violate Bredt’s Rule and prevent the final …
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Activation of diboron reagents: The development of mild conditions for the synthesis of unique organoboron compounds
… a diastereopure, trisubstituted alkene in quantitative yield. Commercially available bis(pinacolato)diboron has shown remarkable stability towards hydrolysis and autoxidation. Using this reagent, we developed a copper- and amine-catalyzed boration protocol performed entirely in water and …
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Asymmetric synthesis of benzylic and heterobenzylic amines
… (DIAZAPs) were prepared by a high-yielding, three-step sequence starting from 2,6-pyridinedicarbaldehyde and (S)-valinol or (S)-phenylglycinol. The new compounds were tested as ligands in palladium-catalyzed allylation of carbanions in different solvents. Almost quantitative yield …
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Synthesis of coordination complexes and the use of X-ray diffraction data towards the development of refinement of occupancy of spherical atoms (ROSA), a new approach for the determination of atomic partial charges
… chemical products generated in high selective yields via efficient syntheses is necessary to provide a sustainable future. Oxidizing hydrocarbons with dioxygen is of particular interest because of substrate abundance. Challenges arise in overcoming the high bond dissociation energy of …
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PURIFICATION OF THE REGULATORY SUBUNIT OF RIBONUCLEOSIDE DIPHOSPHATE REDUCTASE FROM CALF THYMUS
… (B2) subunit. In contrast to the very poor yields reported following dissociation of other mammalian ribonucleotide reductases, dissociation of the calf thymus protein gave a 43% yield. The relatively high value may reflect the greater stability of the subunits from the calf thymus …
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Poly(p-xylylene) Nanotubes Prepared via the Tubes by Fiber Templates Process as Catalytic Nanoreactors
… phenyl propargyl ether. After 17 cycles, the yield was still above 90 %. In contrast to the surface-immobilization of catalysts onto PPX, the suitability of the tubes for encapsulation of transition metal-based catalysts was studied. Polyurethane template fibers featuring incorporated …
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Asymmetrische Synthese von 2-Methyl-substituierten 1,3-Diolen
… acetonide protected ketodiols with good yields and excellent enantiomeric excesses. Since we were looking for new synthetically challenging and pharmacologically interesting targets, we thought about investigating the development of a new reliable method for the asymmetric synthesis of …