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Inaug.-Diss.--Zürich. / Curriculum vitae. "Literatur": p. [17].

The investigation has been concerned with the application of the Baylis-Hillman methodology to the synthesis of quinoline derivatives. An extensive range of novel Baylis-Hillman products has been prepared, typically in moderate to excellent yields, by condensing 2-nitrobenzaldehyde derivatives with various vinyl ketones and acrylic esters in the presence of diazabicyclo[2.2.2]octane (DABCO). Reduction of the nitro group in the Baylis-Hillman products was effected by catalytic hydrogenation in ethanol using a 10% palladium-on-carbon catalyst to afford quinoline, quinoline-N-oxide and quinolone derivatives. In all cases, it is apparent that cyclisation involves exclusive attack of nucleophilic nitrogen at the carbonyl centre, with acrylic ester derivatives affording quinolones and vinyl ketone derivatives affording quinolines and the corresponding quinoline-N-oxides. No products arising from a conjugate addition pathway were observed. The use of stannous chloride as an alternative reagent to effect reductive cyclisation of the Baylis-Hillman products has been explored, and found to favour the formation of 1,2- dihydroquinoline derivatives, with cyclisation occurring via a conjugate addition pathway. Isolation of the products, following work-up of the stannous chloride reactions, however, presented some difficulty. All compounds were characterised by spectroscopic (NMR and IR) and, where appropriate, elemental (high-resolution MS) analysis. Interconversion of the quinoline and quinoline-N-oxide derivatives has been explored and finally achieved in quantitative yields. Reduction of 2,3-dimethylquinoline-N-oxide to the corresponding quinoline was effected using phosphorus tribromide in DMF, and the reverse transformation with meta-chloroperbenzoic acid (MCPBA) in CHCl₃. Application of these methods to mixtures of 2,3-dimethylquinoline and its N-oxide has afforded, selectively, either the quinoline derivative or the corresponding N-oxide. / KMBT_363 / Adobe Acrobat 9.53 Paper Capture Plug-in

Graduation date: 1999

The highly branched hyperbranched polymers (HBPs) possess large inner space among the irregular branches and the inter-chain contacts inside the globular HBPs can be greatly inhibited. With the unique structural features, HBPs have good solubility in common organic solvent and reduced possibility to form excimer and aggregated species. On the other hand, the wholly aromatic polyquinolines are reported to have excellent thermal and oxidative stability. With the above superior properties, HBPs and polyquinolines are commonly used as emitting materials in light-emitting diodes (LEDs). Therefore, quinioline moiety was implanted into HBPS in this study to prepare materials with superior properties to be used in LED pplications. Four polyquinoline HBPs with different branching densities (designated as HBP-1 to -4 from low to high densities) were prepared and their optical, thermal, electrochemical properties and device performance were measured and analyzed. The rigid, wholly heterocyclic polyquinolines HBPs have excellent thermal stability with a high Tg (> 245 ¢J) and high decomposition temperature starting at 571 ¢J. The solution and the solid samples have similar UV-vis absorption and PL emission spectra. The resultant samples have high quantum efficiencies with the measured values ranged from 0.68 to 0.74. Most importantly, thermal annealing at high temperatures (> 200 ¢J) resulted in no changes on the corresponding photoluminescent and electroluminescent emission spectra, which indicates the high thermal and spectral stabilities of all HBP polyquinolines in this study.

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No description available.