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Showing 1 to 20 of 34 for “"cyclopentadiene"”.
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Cyclopentadiene-Maleimide Platform for Thermally Reversible Polymers
… polymers, based on Diels-Alder reactions of bis-cyclopentadienes (bis-CPDs) and bis-maleimides (bis-MIs), that meets two main objectives. First, the bis-CPD must resist characteristic self-coupling. Second, the CPD-MI adducts should undergo the retro-Diels-Alder (rDA) reaction (i.e., thermal …
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Cyclopentadiene as a Platform for Polymer Synthesis and Modification of Macromolecular Systems
… of 1,2-bis(nonafluorobiphenyl-4-yl)-4-tert-butylcyclopentadiene (CPD-1) with N-(4-fluorophenyl)maleimide (FMI) were explored as models for cyclopentadiene-maleimide-based Diels-Alder polymerizations. Mixtures of five endo/exo adducts were obtained, dependent upon CPD-1 tautomers present at …
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Challenging the Limitations of the Streitwieser Lithium Indicator Acidity Scale with Cyclopentadiene Derivatives
… considering various options, cyano-substituted cyclopentadiene derivatives were selected for our study. Because the published methods of synthesizing these compounds were not suited to a routinely equipped academic lab, we developed our own synthetic method based on electrophilic cyanation of …
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Investigation of the synthesis and thermal rearrangements of 1,2,3,4,5-Pentaphenyl-2,4,-Cyclopentadiene Alkyl Ethers
… of a series of six 1,2,3,4,5-pentaphenyl-2,4-cyclopentadiene alkyl ethers was investigated. It was determined that the most efficient route to these ethers was not the most generally accepted route to ethers - the Williamson Reaction - but rather a solvolysis reaction between …
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Pushing the Limits of the Lithium Indicator Carbon Acidity Scale Using Cyclopentadiene Chemistry and 19F NMR Spectrometry
… = 0 by evaluating 23 perfluoroaryl-substituted cyclopentadiene and indene derivatives, using 19F NMR spectroscopy to determine the equilibrium constants of sequential acid-base reactions. This thesis describes the further extension of the SLI scale to ca. pK = −6. To achieve this result, a set …
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Perfluoroarylated Cyclopentadienones: Synthesis, Characterization and Polymerization
… resulting 4,4'-octafluorobiphenylene-linked bis(cyclopentadiene), six perfluoro-4-tolyl groups (three on each of the two cyclopentadienyl moieties) are attached by nucleophilic aromatic substitution (SNAr) reactions. The remaining ring methylenes are subjected to a selenium dioxide-catalyzed …
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Bulky cyclopentadienyl chromium complexes as ethene trimerisation catalyst precursors
… Firstly, a series of known and novel bulky cyclopentadiene ligands, of the type, C₅Ph₄RH (R = H, alkyl, aromatic or substituted aromatic group) were synthesised. Four routes were investigated. (i) Making use of an in situ generated bis-lithium intermediate, resulting in the formation of 1 …
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Green chemistry : dense carbon dioxide and water as environmentally benign reaction media
… in scCO₂, and the cycloaddition between cyclopentadiene and methyl vinyl ketone (MVK) was studied in an scCO₂/liquid water environment. Nitrogen chemistry, specifically the synthesis of nitrogen heterocycles from amines, was also studied in scCO₂ and scCO₂/liquid water systems. The …
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Molecules to engines : combustion chemistry of alcohols and their application to advanced engines
… calculations to indene and naphthalene from cyclopentadiene and cyclopentadienyl radical were performed. The calculated gas phase rate constants and thermochemistry were used to develop the first elementary micro-kinetic model for the formation of indene and naphthalene from cyclopentadiene. …
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Small Molecule Rhenium Carbonyl Complexes: Model Integrated-Design Technetium Estrogen Receptor Ligands for Tumor Imaging
… that inclusion of an acyl substituent on the cyclopentadiene ring lowers the pKa of the ring hydrogens sufficiently for labeling in an aqueous buffer. A divergent synthetic route to a pair of acyl-substituted cyclopentadienyl complexes, along with their alkyl analogs, has been developed. A …
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Total synthesis of (±)-cis-trikentrin B, (±)-herbindole A and (±)-herbindole B. investigation into the regioselectivity of 6,7-Indole aryne cycloadditions
… which underwent Diels-Alder cycloaddition with cyclopentadiene. To complete the synthesis of (±)-cis-trikentrin B, Stille cross-coupling with trans-butenyl tin reagent was employed. The 4,6,7-tribromo-5-methylindole was synthesized via Bartoli indole synthesis. The advantage of using the Bartoli …
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CoMFA Study of Chiral Catalysts
… of N-2-alkenoyl-1, 3-oxazolidine-2-one with cyclopentadiene. It is shown that extemely high q2 statistics can be derived using standard modeling protocols when internal validation alone is done as well as when an external test set is used. From these models it is shown that approximately 70% …
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Supercritical Fluids: Kinetic Solvent Effect and the Correlation of Solid-Fluid Equilibria
Kinetic data for the dimerization of cyclopentadiene at 373, 378, 388, and 398 K in a supercritical propane solvent at pressures from 42 to 136 bar are presented. Data are presented for the cracking of dicyclopentadiene in supercritical butane at 433 K in the pressure range of 42-169 bar. Both …
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The Synthesis and properties of functionalised polymers
… by the reaction of fluorinated dienophiles with cyclopentadiene in a series of Diels-Alder reactions. The monomers were purified and then used in ring opening metathesis polymerisation. The materials were then characterised by gel permeation chromatography and nuclear magnetic resonance …
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Nickel-catalyzed Suzuki-Miyaura reactions of unactivated halides with alkyl boranes and planar-chiral borabenzene catalysts for Diels-Alder reactions
… an asymmetric Diels-Alder reaction between cyclopentadiene and methacrolein catalyzed by a planar-chiral boron Lewis acid. This system exhibits a level of turnover that is unprecedented in reactions mediated by planar chiral boron heterocycles. Computational studies shed light on the nature …
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Sequential cycloadditions for the synthesis of taxoid mimics and stereoselective synthesis of tamoxifen analogues via a new carbomagnesiation-palladium coupling reaction
… with 2-triisopropylsilyl-1,3-butadiene and cyclopentadiene, respectively, gave the tetracyclic skeleton 56 in good yield. Further manipulations afforded compounds 69, 71, and 73, which were subsequently sent for biological testing with the hopes that they will display Taxol-like effects on …
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Segmented Aromatic Polymers Containing Thermally Reversible Linkages
… have main-chain reversible linkages based on cyclopentadiene-maleimide Diels-Alder chemistry. Research in the area of thermally reversible (self-healing) polymers has been an ever-expanding area of interest in the current scientific literature. However most of the emphasis has been on systems …
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Studies Toward Highly Fluorinated Polyphenylenes by Diels-Alder Polymerization
… to give 4,4′-bis[1,2,4-tris(perfluoro-4-tolyl)cyclopentadiene-3-yl]octafluorobiphenyl. Oxidation to the corresponding diketone was effected using selenium dioxide. The synthesis of CPD monomer presented several unexpected challenges that were ultimately overcome. The third chapter describes a …
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Synthesis and cycloaddition chemistry 1,3-Bis(phenylsulfonyl)propadiene
… Reaction with cyclopentadiene, furan, butadiene and Danishefsky's diene has been conducted in a regio- and peri-selectivity study to yield the [4+2] cycloadducts. Treatment of the furan cycloadducts with potassium t-butoxide opened up the oxygen bridge of three …
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Synthesis and Characterization of Cyclopentadienyl Transition Metal Complexes Bearing Tetrafluoropyridyl Substituents
Three new tetrafluoropyridyl-substituted cyclopentadienes were synthesized. Reactions of pentafluoropyridine (C5F5N) with sodium cyclopentadienide (NaCp) in THF with excess NaH present afforded mixtures of (4-tetrafluoropyridyl)cyclopentadiene (1), 1,3-bis(tetrafluoropyridylcyclopentadiene) (2), …
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