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Showing 1 to 20 of 29 for “"regioselectively"”.
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Regioselective Synthesis of Cellulose Derivatives
… to develop novel synthetic methods to synthesize regioselectively substituted cellulose derivatives including cellulose ethers and esters, and apply advanced characterization tools to understand structure and its influence on properties, which will give us deep insights into the composition of …
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Regioselective Synthesis of Novel Cellulose Derivatives for Drug Delivery
… specific synthetic targets of this research were regioselectively carboxylated and regioselectively aminated cellulose derivatives. While different avenues to the carboxylated cellulose were ultimately explored without success, a new method for the synthesis of selectively <i>O</i>-acylated …
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Gold-catalysed reactions of Nitrogen containing molecules
… brominated or silylated 2,4-substituted pyrroles regioselectively. The practical applicability of this process was limited by instability of products under the reaction conditions. Cationic gold catalysis was used in a synthesis of 2,4- and 2,5-substituted pyrroles from alkynyl aziridines. The …
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Regioselective Synthesis of Cellulose Esters
… challenging, especially in the synthesis of regioselectively functionalized cellulose esters due to the unstable ester bond under aqueous alkaline or acid conditions. In this dissertation, the main objective is to search for new tools to synthesize regioselectively substituted cellulose …
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Activation of diboron reagents: The development of mild conditions for the synthesis of unique organoboron compounds
… to selectively transfer the sp2-hybridized boron regioselectively, in the presence of copper, to electron deficient alkenes including α,β-unsaturated ketones, esters, amides, aldehydes, and nitriles to provide the corresponding boratohomoenolates. A unique β,β-diboration of an α,β-acetylenic …
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Investigation of the Steric and Electronic Properties of 3-Iminophosphine Ligands in Chelated Palladium Allyl Complexes for Use in the Regioselective Hydroamination of Allenes
… propensity of the complexes in this series to regioselectively catalyze the hydroamination of 3-methyl-1,2-butadiene with aryl amines to form solely the kinetic product at room temperature was studied by observing conversion to products via NMR spectroscopy. An understanding of the importance …
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Annulation strategies for the synthesis of azulenes and polycyclic nitrogen heterocycles
… on both the five- and seven-membered rings regioselectively. The synthetic utility of the ring expansion annulation products, in particular azulenyl halides and triflates, has been demonstrated by their successful application in transition metal-mediated carbon-carbon bond forming reactions. …
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Regioselective chlorination of cellulose esters
… successfully developed a method to chemo- and regioselectively chlorinate cellulose esters using MsCl. Compared to bromination of cellulose typically used, this chlorination method has many advantages, including low cost of reagents and ease of separation. The chlorinated cellulose esters are …
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Studies towards the Organocatalytic ‘Dialled In’ Synthesis of Chiral, Non-Racemic Aziridines, and Amino Acids, Containing Multiple Isotopic Labels
… enriched a-amino acid derivatives bearing regioselectively introduced deuterium labels (with generally >90 % isotopic enrichment), in yields of up to 97 %, and e.e.s of up to 97 %, Finally, these methods have been combined in order to synthesise 5 target molecules consisting of …
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2,3-Dihalofenoles: sustratos de partida versátiles para la síntesis de heterociclos funcionalizados regioselectivamente
… developed efficient routes to the synthesis of regioselectively functionalized indoles, benzo[b]furans and benzo[b]thiophenes. The directed ortho-metalation strategy in conjunction with palladium-catalyzed cross-coupling reactions have been mainly used to achieve this goal. The potential of …
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Palladium -catalyzed synthesis of carbazole derivatives and formal total syntheses of several naturally occurring carbazole alkaloids
… Methyl-substitution on the cyclohexenone ring regioselectively produced methyl-substituted tetrahydrocarbazoles, however substitution on the benzene ring led to mixtures of carbazole products.
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Regioselective synthesis of curdlan derivatives
… synthesis and characterization of a family of regioselectively aminated curdlan derivatives including 6-deoxy-6-(bromo/azido/amino/amido/ammonium) curdlans starting from 6-bromo/azido-6-deoxycurdlan. A key reaction that enabled the whole synthesis of new curdlan derivatives at C-6 described in …
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Development of Pd Catalyzed Amidations & Applications to the Synthesis of Heterocycles
… These pyridines were used to synthesize regioselectively substituted imidazo[4,5-c]pyridines using a Pd-catalyzed amide coupling reaction.</p> <p>Chapter 6</p> <p>A regioselective palladium-catalyzed amidation of polychlorinated aminopyridines was accomplished to provide chlorinated …
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ΜΕΛΕΤΗ ΑΝΤΙΔΡΑΣΕΩΝ 1,3-ΔΙΠΟΛΙΚΗΣ ΚΥΚΛΟΠΡΟΣΘΗΚΗΣ ΣΕ ΕΤΕΡΟΚΥΚΛΙΚΑ ΣΥΣΤΗΜΑΤΑ
… WERE ALSO EXAMINED. THESE REACTIONS SHOW THESAME REGIOSELECTIVELY AND GIVE THE SAME PRODUCTS OBTAINED FROM THE METHANOLYSIS OF THE (Z)- AND (E)-SPIRO CYCLOADDUCTS RESPECTIVELY, CONFIRMING THAT NUCLEOPHILIC CLEAVAGE OF OXAZOLONE-RING IS STEREOSPECIFIC.
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Synthesis and Applications of Cellulose Derivatives for Drug Delivery
… delivery applications, methods were developed to regioselectively modify C-6 halo cellulose esters to produce cationic derivatives via nucleophilic substitution. Reaction of C-6 substituted bromo and iodo cellulose with trialkylated amines and phosphines produced new cationic ammonium and …
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Metal-Catalyzed Formation and Transformations of Carbon-Boron Bonds
… reagent, pinB-Bdan. The reaction proceeds regioselectively in high yields to furnish olefins bearing a vinylic Bpin and an allylic Bdan moiety. The subsequent chemoselective transformation of each boron center was demonstrated. Methods for preparing 1,8-diaminonaphthalene protected …
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Fullerene-acene chemistry: Part I Studies on the regioselective reduction of acenes and acene quinones; Part II Progress toward the synthesis of large acenes and their Diels-Alder chemistry with [60]fullerene
… acenes with as many as seven rings will reduce regioselectively to leave the internal terphenyl moieties intact. In the cases of 6,13-diphenylpentacene and 5,7,12,14-tetraphenylheptacene quinone, reduction occurs at alternating rings such that the end rings and the internal terphenyl moieties …
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Tetraazamacrocyclic ligands and their copper complexes
… using organolithium reagents appears to proceed regioselectively. An X-ray structure determination of the copper complex of 5,12-dimethyl-5,6,11,12, 18,19,20,21-octahydro-17-H-tribenzo (f,j,n)(1,5,9,12) tetraazacyclopentadecine shows this to be meso-dimethyl isomer. Condensation of 2,2 …
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The development and applications of unsymmetrical diboron compounds
… series of 1,1- disubstituted allenes chemo- and regioselectively. Steric control ensures that both boryl moieties add to the terminal double bond, and the pinacol boronate preferentially attaches to the sp-hybridized carbon. The bis-boronyl products can be further converted to other functional …
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Studies in the synthesis and analysis of novel heterocyclic synthetic cannabinoid receptor agonists
… optimised N-alkylation protocol is also shown to regioselectively (> 99%) afford N-2 substituted indazoles. Through the variation of “tail” and “head” group motifs inspired by structural trends observed in newly emerging cannabimimetic SCRA NPS, we have generated a prophetic library of novel …
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