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 20 of 119 for “"Cyclisation"”.
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Reductively triggered internal cyclisation reactions
Reductively triggered internal cyclisation reactions have been investigated as a prodrug system for the hypoxia selective release of aromatic nitrogen mustards. The observed pseudo-first-order rate coefficients of cyclisation of several model 2-aminoaryl-acetamides and propanamides have been …
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Synthèse de dérivés de l'oestradiol par cyclisation anionique
… des dérivés de l'oestradiol de la réaction de cyclisation anionique développée au laboratoire pour la synthèse de composés de type stéroïdique. Il décrit d'abord la synthèse des précurseurs nécessaires aux cyclisations. Les résultats des cyclisations sont ensuite présentés puis, une brève …
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Development of Novel Self-Immolative Linkers based on Fragmentation and Cyclisation Reactions for Targeted Therapeutic Applications
La terapia dirigida se ha erigido a lo largo de los últimos años como una de las estrategias más prometedoras para el tratamiento del cáncer. Estos sistemas consisten en una molécula con una alta afinidad y selectividad hacia una diana presente en células cancerosas, conjugada a fármacos …
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Radical cyclisation studies of chiral α-acylamino radicals : a model study towards Tacaman indole alkaloid synthesis
he radical cyclisation of chiral 4,5-substituted N-acyl-2-aza-6-heptenyl radicals, derived from D-ribose, has been undertaken as a model stuay towards Tacaman indole alkaloid synthesis. The radical cyclisations were conducted using tributyltin hydride/AIBN in refluxing benzene. The α-acylamino …
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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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Study of the mechanism of cyclisation in the preparation of dioxazines and developments of synthetical methods based upon the results
The work was roughly divided into two sections. The first involved the preparation of known triphenodioxazine pigments and the purification and examination of their properties which had not been hitherto carried out. Much adaption of existing methods for the preparation of 1-aminopyrene and …
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Total synthesis of ferrugine and synthetic studies towards ferrugine and stemofoline
… was achieved using a transannular photomediated cyclisation of a carbamoyl radical, generated from a carbamoyl diethyldithiocarbamate, onto an unactivated pendant alkene, followed by group transfer of the dithiocarbamate moiety. The carbamoyl radical cyclisation precursor was synthesised from a …
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Étude de précurseurs de radicaux amidyles et de l'oxydation électrochimique du 5-aminoindole
… primaires ou secondaires pouvant conduire par cyclisation intramoléculaire à un hétérocyle fonctionnalisé. De tous les nouveaux précurseurs de radicaux amidyles imaginés, un seul a été préparé soit le N-benzoyloxy-N-méthyl-3-cyclohexènecarboxamide, un précurseur de radical amidyle secondaire. …
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Asymmetric synthesis of novel anthracyclinones
… anthracyclinones by Lewis acid promoted cyclisations of ortho-methallyl anthraquinonyl chiral dioxanes has been investigated. Tin tetrachloride-N,N-dimethylformamide promoted cyclisation of the dioxane (30) proceeded with excellent stereoselectivity to give an 82% yield of the …
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Synthetic Investigations towards the Total Synthesis of Neuroprotective Natural Products
… (12) were initially directed towards cyclisation of diarylamines 175. Attempts were made to elaborate diarylamines 175 with a view to produce the tricyclic α-carboline core of 12 via cyclisation to form the central pyrrole ring. Difficulties effecting the cyclisation of 175 led us to …
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A study of alkylation reactions α- to nitrogen for application in alkaloid synthesis
… 1-a]isoindolones, via radical and carbanionic cyclisation of a Ntethered α-sulfanyl lactam incorporating an enoate ester as the acceptor and an allylic tertbutyldiphenylsilyloxy group (OTBDPS) as stereocontrol element. The product stereochemistries have successfully modelled the required …
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Total synthesis of cis-sylvaticin and synthetic studies towards the synthesis of adjacent THF-THF and THF-THP Annonaceous acetogenins
… two permanganate promoted oxidative cyclisation reactions, a tethered<br/>RCM to unite the two major fragments and the use of P4 phoshazene base to<br/>install the butenolide precursor.<br/><br/>Synthesis of adjacent THP-THF and bis-THF cores via cascade oxidative<br/>cyclisation …
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Radical Approaches to Alangium and Mitragyna Alkaloids
… The approaches include the use of a key radical cyclisation to form the tri-cyclic core. Chapter 1 gives a general overview of radical chemistry and it focuses on the application of radical intermolecular and intramolecular reactions in synthesis. Consideration is given to the mediator of radical …
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Chemistry of the Degradation of Vinyl Polymers to give Carbon Fibre Precursors
… of a hydrogenated naphthyridine structure by cyclisation of the nitrile groups in the polymer. An alternative mechanism for the depradetion under these conditions is proposed. Before cyclisation the propogating ketimine groups (>C =H) undergo tautomeric rearrangement to the enamine form ( …
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Synthesis of Cylindricine C and its Stereoisomers
… a tandem conjugate addition and intramolecular cyclisation of a key intermediate β-amino ester. Key steps in our synthesis involve a Curtius rearrangement to install the nitrogen at the quaternary center and an electrophilic cyclisation to construct the tricyclic core. Desulfonylation and …
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Formation of 2,5-trans-tetrahydrofuran-3-one application towards the synthesis of natural products
… can be converted to the desired cyclisation product via oxidative cyclisation with molecular oxygen using cobalt complex as a catalyst. The 5-hydroxy-1-alkene react with the Co complex and the oxygen. The radical complex thus formed could be converted to the cyclised intermediate. …
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Total Synthesis and Stereochemical Revision of Pestalospirane B
… the use of a novel double oxidative radical cyclisation to construct the 7,6-membered spiroketal moiety of pestalospirane core 114. The first model study explored several synthetic approaches for the construction of the key substituted 1,4-dioxane intermediate 115 for application in the total …
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Towards the total synthesis of Agariblazeispirol C
… on the strategic employment of metal-mediated cyclisation chemistry, specifically, a novel intramolecular Heck reaction and an intramolecular Pauson-Khand cyclisation. With regards to the construction of the main core of the molecule, the synthesis of a late stage intermediate has been …
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Synthesis and kinetics of isomerisation of 2',6'-dihydroxychalcones
… have been analysed in terms of contributions to cyclisation and ring opening of the various ionised chalcone and flavanone species, and individual rate and equilibrium constants for all the contributing reactions have been determined. Rate measurements with D₂O as the solvent (for 32, 34, 36, 38, …
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