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 20 for “"Heterocyclic systems"”.
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Preparation and properties of some polycyclic heterocyclic systems
Typewritten copy
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Bicyclic Heterocyclic Systems Derived from 1, 3, 4-Trisubstituted Pyridines
… pyridines and their conversion into bicyclic systems are reviewed. The work described in this thesis concerns the preparation of 1,3,4-trisubstituted pyridines, by both existing and novel routes, and the conversion of these precursors into bicyclic systems. Nucleophilic displacement of the …
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Cross-Coupling Chemistry as a Tool for the Synthesis of Diverse Heterocyclic Systems and Natural Products
… of the Resulting Products To Give Diverse Heterocyclic Systems'. The third publication has the title 'Reductive Cyclization of o-Nitroarylated-alpha,beta-Unsaturated Aldehydes and Ketones with TiCl3/HCl or Fe/HCl Leading to 1,2,3,9-Tetrahydro-4H-carbazol-4-ones and Related Heterocycles'. …
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Cross-Coupling Chemistry as a Tool for the Synthesis of Diverse Heterocyclic Systems and Natural Products
… of the Resulting Products To Give Diverse Heterocyclic Systems'. The third publication has the title 'Reductive Cyclization of o-Nitroarylated-alpha,beta-Unsaturated Aldehydes and Ketones with TiCl3/HCl or Fe/HCl Leading to 1,2,3,9-Tetrahydro-4H-carbazol-4-ones and Related Heterocycles'. …
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Synthesis of 4-(trifluoromethyl)azetidin-2-one building blocks and their transformation into novel CF3-substituted amines and heterocyclic systems
… class of building blocks. The aptitude of these systems with respect to ring-opening reactions was explored to enable an entry to functionalized aminopropane systems by either direct reductive β-lactam ring opening or initial carbonyl removal to azetidine intermediates, followed by ring opening. …
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Synthesis Of 6-Nor-5,7-Seco-5-Ketal- 7,7-Diphenylcholest-7-Ene
… or more of the carbocyclic rings is replaced by heterocyclic systems may be expected to have interesting physiological properties. Compounds of this kind with vicinal diaza systems are rare, and none in the B-ring of cholesterol is known. | The present investigation was undertaken in an attempt …
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Synthetic and computational investigations into reaction pathways towards complex heterocyclic ring systems
… The development of new synthetic routes to novel heterocyclic systems has remained a critical branch of synthetic organic chemistry due to potential applications in biomimetics and pharmaceuticals, such as dyes and explosives. 1,2,3,5-tetrazocines were originally proposed as an intermediate in the …
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Exploration of Synthetic Pathways to Quaternary Carbon Stereocenters and Fused Ring Systems via Birch Reductions
… sequence to make 6-5-6 and 6-6-6 carbocyclic and heterocyclic systems. In all of these examples the Birch reduction alkylation has been the key step and we have demonstrated broad applicability and the use of some of the most complex alkylating agents to date.</p>
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Halogenated Heterocycles for Drug Discovery
… a wide range of products to be synthesised. Heterocyclic compounds are particularly sought after as useful compounds, with an estimated 70% of pharmaceutical products being based on heterocyclic structures. A drawback of many traditional routes towards heterocyclic compounds is that the range …
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Carbenoid insertions and cyclometallations of zirconacycles
… to produce a wide variety of<br/>carbocyclic and heterocyclic systems is well established. This thesis focuses on the<br/>insertion of chloro(aryl)methyllithiums (benzyl carbenoids) into a range of<br/>zirconacyclopentenes and zirconacyclopentanes.<br/><br/>Benzyl carbenoid insertion into a …
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Development of a Ni-Catalyzed Enantioselective Intramolecular Mizoroki- Heck Reaction for the Synthesis of Phenanthridinone Derivatives
… provides direct access to six-member ring heterocyclic systems bearing all-carbon quaternary stereocenters, which have been much more challenging to form enantioselectively with nickel-catalyzed Heck reactions. The first part of this project describes important advances in reaction …
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Síntesis de nuevas sondas cromogénicas a partir de heterociclos de azufre y nitrógeno
… The study of heterocyclic systems have a prominent place in the field of organic chemistry and is perhaps one of the areas that best reflect the interplay between basic and applied research because of the large number of applications that have been found for …
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Cycloadditions to 1-azetines and 1-azetin-4-ones
… the C=N bond of 1-azetines would yield bi-cyclic systems of related structure to the beta-lactam nucleus of beta-lactam antibitics.Thus, three 1-azetine systems (2-4) were prepared by alkylation of their precursor azetidinones and thioazetidinones.The ability of these systems to enter into …
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Studies on extensions of tert-amino effect: Ring-fusion to bridged biaryls and steroids
… tertiary anilines to benzo-fused heterocyclic systems. In type 2 reactions, an ortho-vinyl tert-aniline gives a tetrahydroquinoline via C-C bond formation between the beta-vinyl carbon and the alfa-methylene carbon of the amino group; the reaction could be extended to heterocyclic …
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Synthesis of New Alkyn-1-ylsilanes. 1,1-Organoboration, 1,2-Hydroboration
… groups were used for the synthesis of different heterocyclic systems e.g., 1-silacyclobutenes, 1-silacyclopent-2-enes, siloles, borolenes, etc. Intermediates of sufficient stability and final products were studied by multinuclear NMR spectroscopy (1H, 11B, 13C, 29Si and 119Sn NMR). Numerous …
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Exploration of Transition Metal Catalyzed C−C and C−N Bond Formation to Access Synthetically Elusive Small Molecules
… and palladium catalysis, accessing underexplored heterocyclic motifs. The utility of these techniques toward the synthesis of small molecules in drug discovery cannot be understated, as there are few ways to access these elusive moieties. The content is divided into the following four …
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Novel small molecules for modulation of bacterial signaling pathways
… (AHLs), indoles, N-acetyl glucosamine and other heterocyclic systems derived from halogenated furanones (Fimbrolides). Indole and glucosamine-based amides and oxo-amides were synthesized as non-native AHL mimics by applying EDC, DCC or EDC/HOBt mediated amide coupling methods. On docking study, …
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Arilglioxales en reacciones Passerini y Ugi. Síntesis de heterociclos
Los compuestos heterocíclicos son núcleos muy importantes en el desarrollo de nuevos fármacos por la amplia variedad de propiedades farmacológicas que poseen. Esta tesis se ha centrado en el desarrollo de nuevas metodologías sintéticas de sistemas con un gran impacto como son los núcleos de …
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Antimalarial imidazopyridazines and aminopyrazines: synthesis, physicochemical optimization and structure-activity relationships
… rings with fully and partially saturated heterocyclic systems, hypothesized to potentially disrupt intermolecular π – π stacking thereby improving aqueous solubility, were introduced. The first set of analogues corresponded to the replacement of the trifluoromethylpyridyl ring with …