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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 51 for “"Carbonyl Groups"”.
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Polymeranaloge Carbanilierung von Cellulose
… in pyridine occurs via beta-elimination at carbonyl groups along the cellulose chains. Carbanilierung in DMSO is much more pronounced. It comprises oxidation along the Pfitzner-Moffatt-mechanism and subsequent beta-elimination at the thus formed carbonyl-groups. This was elucidated with …
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Formation, characterization, and chemical reactions of free radicals in lignin
… of lignin phenyl propane units took effect in α-carbonyl group bearing molecules. By contrast, β aryl ether substituents adjacent to α-carbonyl groups caused ether cleavage under identical conditions of photoirradiation. This is attributed to energy transferred from excited α-carbonyl groups to …
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Highly Active Iron-NHC Complexes for Carbonyl Hydrosilylation
The catalytic hydrosilylation of carbonyl groups into alcohols is a powerful transformation in the laboratory and industry. Despite the recent advances in this field, the development of catalytic systems that can activate inexpensive silanes like polymethylhydrosiloxane (PMHS) under mild conditions …
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Modeling of Atmospheric Pressure Plasma Processing of Gases and Surfaces
… surface densities of alcohol, peroxy, acid, and carbonyl groups. However, significant amounts of O3 and NxOy are generated in the gas phase. Increasing the relative humidity results in decreased production of O3 and increased concentrations of peroxy and acid groups on the surface. Increasing the …
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Multicomponent Cyclization Reactions: A General Approach To Dibenzocyclooctadiene Lignan Natural Product
… for different reactivities of certain functional groups (e.g.,C-C double bonds, hydroxyl and carbonyl groups), which can explain the stereochemicaloutcome of related transformations, for example, the hydrogenation reactions, Mitsunobureactions, electrophilic additions to C-C double bonds and …
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Characterization of native and bypass human coronary artery plaque deposits from the same heart: investigation of the chemical form of calcium in human coronary artery plaque deposits
… same heart indicated that the concentrations of carbonyl groups, typical of cholesterol esters, were similar between the native and bypass arteries. Significant signals of carbonyl groups in the crystalline and amorphous plaques were due to amino acids and proteins deposited in the plaques. …
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Thiol Dough Conditioners Impact on the Formation of Advanced Glycation End-products in Bagels Containing Sunflower Seed Flour
… group undergoing nucleophilic attack to the carbonyl groups of the reducing sugars present, forming hemithioacetals, hence scavenging of carbonyl groups, making them unavailable for further reaction to form AGEs. 0 to 10 % SFF and 25 and 90 ppm GSH significantly lowered AGE formation in …
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Surface analysis of sheet molded composite (SMC) material as related to adhesion
… including -C-0·R(X)/-NCOZR and -C=0 (ester carbonyl) groups, were found to promote good adhesion using urethane adhesives. These chemical functionalities_were particularly enhanced after treating the SMC surface with an isocyanate primer as well as after a solvent/abrasive surface …
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Nickel-catalyzed Suzuki-Miyaura reactions of unactivated halides with alkyl boranes and planar-chiral borabenzene catalysts for Diels-Alder reactions
… This work constitutes an extension directing groups for the asymmetric Suzuki-Miyaura reactions halides. ... Part II details work towards an asymmetric Diels-Alder reaction between cyclopentadiene and methacrolein catalyzed by a planar-chiral boron Lewis acid. This system exhibits a level of …
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The detection and characterisation of novel alkyl spin-adducts of PBN and its derivatives using capillary gas chromatography coupled to electron-ionisation mass spectrometry
… are strong electrophilic compounds with terminal carbonyl groups making them highly reactive. Aldehydes may react with hydroxyl radicals forming radicals which, in turn, react with cellular components. Hydroxyl free radicals were generated by Fenton-based chemistry and reacted with aliphatic …
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Applications of 2,3-Diketoesters in Organic Synthesis and Stereoselective Transformations
… of 2,3-diketoesters was demonstrated in carbonyl-ene reactions catalyzed by [Cu((S,S)-tert-Bu-box)](SbF6)2 generating chiral α-functionalized-α-hydroxy-β-ketoesters in up to 94% yield and 97% ee. The suggested mode of activation is bi-dentate coordination between copper and the oxygen …
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Seasonal and diel periodicity of Cerambycid beetles in east-central Illinois: the potential for cross attraction
… motif of a six-carbon chain with hydroxyl or carbonyl groups at C2 and C3, and closely related species often share pheromone components, or even produce pheromones of identical composition. This parsimony in pheromone structure often results in multiple species being attracted simultaneously …
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Ion Selectivity and Gating in the NAK Channel
… Ca2+ chelation chemistry involving only backbone carbonyl groups as ligands, with Ca2+ selectivity at the extracellular site mediated by a through space interaction with a conserved acidic residue, Asp66, seen in other Ca2+ conducting channels. In the high resolution structure of the truncated NaK …
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Novel Materials for Use in Homeland Security Research
… with the respective metal bound to five carbonyl groups and one bromide (MnCO5Br, ReCO5Br). Our research focused on the synthesis of a variety of 5,6-fused ring pyridazines that will act as a model for homeland security research in polymer studies and medicinal research. Synthesis and …
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Some Aspects of the Chemistry of Sulphur Halides and Oxyhalides
… conditions and the structure of the adjacent groups. This work partly deals with the reactions of thionyl chloride with 1,3-diketones which afforded sulphides and o-chlorides. Typically, dimedone gave di-2-hydroxy-4,4-dimethyl- ~6-oxocyclohex-1-enyl sulphide and …
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Development of an analytical method to quantify the oxidative deoxyribose damage product 3'-phosphoglycolaldehyde induced by radiation, iron and peroxynitrite
… forms strongly electrophilic terminal blocking groups and abasic sites capable of stopping polymerases, forming DNA-protein crosslinks and nucleobase adducts. These threats to the genetic integrity of cells are caused by exogenous and endogenous oxidizing agents and may contribute to diseases …
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Synthesis of derivatives of 4H-cyclopenta[ def]phenanthren-4-one and development of synthetic strategies for the polycyclic aromatic hydrocarbons with carbon frameworks represented on the surface of C60
… corresponding diketone 93. The presence of two carbonyl groups allowed a second condensation with the lithium acetylide 79 to afford the propargylic alcohols 94 and 95. Treatment of 94 with thionyl chloride using the same procedure as described for 56a and 80 afforded the two isomeric …
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Functionalised polymers
… routes to polymers possessing functional groups were studied. Direct functionalisation of poly(vinyltoluene) by lithiation and carboxylation resulted in the expected carboxylic acid but reaction was complicated by the production of a mixture of products. Reaction occurred both at the …
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AN INVESTIGATION INTO THE ANALYTICAL UTILITY OF CHANGES IN POLARIZATION ACCOMPANYING ANALYTICAL DERIVATIZATION REACTIONS (FLUORESCENCE)
… reactions between amines, alcohols and carbonyl groups with various reagents were studied. The goal of the work discussed in this dissertation was to generate basic data to know whether and in what context changes in fluorescence polarization are useful for following analytical …
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