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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 94 for “"Epoxides"”.
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THE EFFECT OF WATER ON THE PHYSICAL PROPERTIES OF EPOXIDES
… technique to accelerate water diffusion in bulk epoxides. The boiling-water diffusion was found to be Fickian in epoxides except for the DOM system’, water-vapour diffusion at 25°C was found to be Fickian. To study accurately the effect of water absorption (liquid and vapour) on the mechanical …
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Reactions of a super-electron donor with diarylcyclopropanes and epoxides
… oxirane was observed. Scheme 1 - Reactivity of epoxides with electron donor 1.57. The geometric isomerisation of diarylcyclopropanes was also achieved by DMAP-derived electron donor 1.57. Both geometric isomers of 1,2-bis(4-fluorophenyl)cyclopropane and 1,2- diphenylcyclopropane were isomerised …
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Syntheses and Determinations of Absolute Configuration and Enantiomeric Composition of Chiral Oxaziridines and Epoxides
Made available in DSpace on 2014-12-13T20:10:34Z (GMT). No. of bitstreams: 1 7913591.pdf: 4509905 bytes, checksum: cc327a7c32ec6093eae05e3f286c0cec (MD5) Previous issue date: 1978
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The Photochemical Cyclisation of N-Styryl Compounds Produced During an Investigation into the Reactions of Imidazoles with Epoxides
Please see Thesis for the abstract.
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Stereospecific alkynylation at the more hindered carbon of trisubstituted epoxides and concise syntheses of bis-THF acetogenins and analogues
… at the tertiary position of trisubstituted epoxides in 75-80% isolated yield. The reaction is stereospecific with inversion at the substitution center. This work constitutes the first general method for the addition of a carbon nucleophile at the more congested site of a trisubstituted …
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Studies on the use of peptide auxiliaries in the meso-desymmetrization of epoxides, and the kinetic resolution of secondary alcohols
This thesis reports on the use of amino acids and peptides as chiral ligands/catalysts in two asymmetric processes: Meso-desymmetrization of an epoxide and the kinetic resolution of secondary alcohols. Chapter 1 comprises a literature review, which gives a general overview of methods of asymmetric …
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Part I. Solvolysis of Caryophyllen-8-Yl Derivatives: Model Reactions for Presilphiperfolanol Biogenesis. Part II. Stereochemistry of Lithium-Amine Reductions of Tetrasubstituted Epoxides and Phenylthiohydrins to Tertiary Alcohols
… reductions of model bicyclic tetrasubstituted epoxides and the corresponding trans-phenylthiohydrins was carried out to determine the stereochemistry and optimal reaction conditions for this transformation. Octalin, hydrindene, and bicyclo (3.3.0) octene epoxides were synthesized, and the …
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Studies of the Synthesis of Polycyclic Homocyclopropylcarbinols
… been realized by lithiation of bromocyclopropyl epoxides with n-butyllithium and subsequent intramolecular attack of the metallated cyclopropane ring onto the epoxide. A series of bromocyclopropyl epoxides was prepared from diene precursors in three or four steps by dibromocyclopropanation, …
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Microwave-assisted synthesis of ß-amino alcohols
… moieties is by ring opening of unsymmetrical epoxides using amines via a substitution reaction. However, the majority of these methods requires excess of reagents, inorganic initiators, and/or extended reaction times. We have developed an efficient, regioselective route to synthesize amino …
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TOWARDS SUSTAINABLE CATALYSIS: DESIGN OF EARTH-ABUNDANT METAL COMPLEXES FOR WASTE VALORIZATION
… chapter: Cycloaddition of carbon dioxide and epoxides with pyclen metal complexes (zinc and iron) as catalysts. Developement and optimization of the reaction without the addition of external nucleophilic co-catalysts. Third chapter: Cycloaddition of carbon dioxide to epoxides and aziridines …
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The bioactive role of omega-3 endocannabinoid epoxide regioisomers
… (EDP-EAs) that are known as omega-3 eCB epoxides. Previously, 17,18-EEQ-EA and 19,20-EDP-EA have shown to have anti-neuroinflammatory, vasodilatory, anti-angiogenic properties, activate cannabinoid receptors and regulate platelet aggregation in vitro. Although these metabolites have …
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Development of a microwave-assisted epoxide aminolysis and investigation of the aza-cope rearrangement--mannich cyclization for alkaloid synthesis
… β-amino alcohols are prepared by ring opening of epoxides using an amine nucleophile and a catalyst or promoter. Ring opening can take place by the SN1 pathway or the SN2 pathway, but no single catalyst or promoter consistently gives SN2 selectivity. Additionally, long reaction times are often …
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Asymmetric synthesis involving silicon
… more useful, optically active trimethylsilylepoxides, 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 …
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Computational Studies of Protonated Cyclic Ethers and Benzylic Organolithium Compounds
Protonated epoxides feature prominently in organic chemistry as reactive intermediates. Gas-phase calculations studying the structure and ring-opening energetics of protonated ethylene oxide, propylene oxide and 2-methyl-1,2-epoxypropane were performed at the B3LYP and MP2 levels (both with the …
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Nickel-catalyzed reductive coupling reactions : application to the total syntheses of pumiliotoxins 209F and 251D
… Reductive Coupling of 1,1-Disubstituted Epoxides and Alkynes: Total Synthesis of Pumiliotoxin 209F and 251D Pumiliotoxins 209F and 251 D were prepared using a novel nickel-catalyzed intramolecular cyclizations between alkynes and 1,1-disubstituted epoxides. These cyclizations formed …
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Synthesis and properties of lignin epoxide
… with IR, ¹H and ¹³C NMR spectroscopy. Lignin epoxides were cured by crosslinking with a diamine and with phthalic anhydride. An amine-terminated rubber was added as toughening agent. Sol fraction and swelling behavior, stress-strain behavior and dynamic mechanical behavior of the cured lignin …
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Synthesis of furanosesquiterpenoid natural products
… bromide complex with a range of epoxides, this complex was found not only to react with reactive epoxides (e.g. styrene epoxide) but also with less reactive propylene epoxide.<br/><br/>Substrates for possible intramolecular n-allylnickel cyclisation to generate an …
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A scalable protocol for the synthesis and use of neomenthyldiphenylphosphine.
… The endo-selective cyclization of alcohols onto epoxides provides a direct route for constructing the oxygen heterocycles found in ladder polyether natural products. Additionally strategies to transform multiple epoxides into multiple new rings have appealing parallels to the proposed biogenesis …
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FREE-BASE PORPHYRIN FOR CO2 ACTIVATION
… drastic conditions. Even if the reaction between epoxides and CO2 has been deeply studied in the last 20 years, 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 …
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