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Allylic substitution is an important procedure for carbon-carbon, carbon-nitrogen and carbon-oxygen bond formation, and palladium-mediated allylic substitution reactions have previously been employed in the synthesis of a range a physiologically active and natural products. 2,5-Dicarbon substituted 2,5-dihydrofurans have not to date been synthesised by palladium-mediated allylic substitution reactions. It was found in the first part of the work that allylic substitution reactions of 2,5-diacetoxy-2,5-dihydrofuran with a tertiary carbon nucleophile did not result in the desired mono-substitution product due to the elimination of acetic acid from the product, to form the aromatised furan derivative. In an attempt to differentiate between the two potential leaving groups on the dihydrofuran, one of the acetate groups was displaced in a palladium-mediated allylic substitution reaction. This approach was also intended to inhibit the aromatisation reaction. The desired product 2-acetoxy-5-phenoxy-2,5-dihydofuran was obtained. The palladium-mediated allylic substitution reactions of this product with a range of tertiary carbon nucleophiles provided the desired mono-substituted dihydrofuran products in good yield with minimal by-products being detected. The substitution of the phenoxy-leaving group with a carbon nucleophile, however, was not achieved under a range of reaction conditions. Other more electrondeficient phenol derivatives were used in the initial substitution reactions but due to time constraints the work could not be completed in the current study. This would hopefully have increased the leaving group ability of the phenoxy group and the desired disubstituted dihydrofuran would have been achieved, and this will be the subject of further work in this regard. Milder reaction conditions were applied to 2,5-diacetoxy-2,5-dihydrofuran in its reaction with a tertiary carbon nucleophile. The desired mono-substituted mono acetoxy products were obtained in reasonable yields when column chromatography was performed at –15 °C and the silica was neutralised with Et3N. These mono-acetoxy products were reacted with a range of tertiary carbon nucleophiles and the desired disubstituted dihydrofurans could be prepared in reasonable yields. One-pot reactions were investigated by using three equivalents of nucleophile and in most cases the desired symmetrical dihydrofuran was achieved. This result prompted the investigation into the synthesis of disubstituted dihydrofurans in a one-pot reaction by successive addition of two carbon nucleophiles with 2,5- diacetoxy-2,5-dihydrofuran. The disubstituted dihydrofurans were isolated in higher yields than the two-pot procedure and the complex purification procedure developed was not necessary. This study, therefore, allowed for the synthesis of a range of symmetrical and unsymmetrical dicarbon substituted dihydrofurans. This methodology will later be applied to the synthesis of a range of natural products. / Prof. D.B.G. Williams

by Lee Wai Lok. / x and 1-x are in title are subscript. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves [67]-[70]). / by Lee Wai Lok. / Abstract --- p.i / Chapter Chapter1 --- Introduction --- p.1-1 / Chapter 1.1 --- Epitaxial Growth --- p.1-2 / Chapter 1.1.1 --- Background of Epitaxy --- p.1-2 / Chapter 1.1.2 --- Operating Principle of OMVPE --- p.1-2 / Chapter 1.1.3 --- Problems in Heteroepitaxy --- p.1-3 / Chapter 1.2 --- Basic Requirements of a Semiconductor Laser --- p.1-3 / Chapter 1.3 --- Our work --- p.1-4 / Chapter Chapter2 --- OMVPE Growth --- p.2-1 / Chapter 2.1 --- Our OMVPE System Design --- p.2-1 / Chapter 2.1.1 --- Growth Environment --- p.2-2 / Chapter 2.1.2 --- Susceptor Temperature Control --- p.2-2 / Chapter 2.1.3 --- Reactor Pressure Control --- p.2-2 / Chapter 2.1.4 --- MO Vapor Handling Control --- p.2-2 / Chapter 2.1.4.1 --- MO Flow Control --- p.2-3 / Chapter 2.1.4.2 --- Flow Path Selection --- p.2-3 / Chapter 2.1.5 --- Cabinet with Air Extraction --- p.2-3 / Chapter 2.1.6 --- Chemical Scrubber --- p.2-4 / Chapter 2.2 --- System Calibration --- p.2-4 / Chapter 2.3 --- Materials Used --- p.2-5 / Chapter 2.3.1 --- Precursor Materials --- p.2-5 / Chapter 2.3.2 --- Hydrogen Gas --- p.2-5 / Chapter 2.3.3 --- Nitrogen Gas --- p.2-6 / Chapter 2.3.4 --- Substrate --- p.2-6 / Chapter 2.4 --- Fabrication Conditions --- p.2-6 / Chapter Chapter3 --- Characterization --- p.3-1 / Chapter 3.1 --- X-ray Diffraction --- p.3-1 / Chapter 3.2 --- EDX Spectroscopy --- p.3-2 / Chapter 3.3 --- Optical Reflectance --- p.3-4 / Chapter Chapter4 --- Data Analysis --- p.4-1 / Chapter 4.1 --- ZnSe/GaAs(100) --- p.4-1 / Chapter 4.1.1 --- Structural Analysis --- p.4-1 / Chapter 4.1.2 --- Stoichiometry --- p.4-2 / Chapter 4.1.3 --- Growth Rate --- p.4-3 / Chapter 4.1.4 --- Energies of Critical Points --- p.4-3 / Chapter 4.1.5 --- Reflectance --- p.4-4 / Chapter 4.2 --- ZnCdSe/InP(100) --- p.4-5 / Chapter 4.2.1 --- Structural Analysis --- p.4-5 / Chapter 4.2.1.1 --- Structural Quality --- p.4-5 / Chapter 4.2.1.2 --- Crystal Structure --- p.4-5 / Chapter 4.2.1.3 --- Lattice Parameter --- p.4-8 / Chapter 4.2.2 --- Composition Range --- p.4-8 / Chapter 4.2.3 --- Degree of Relaxation --- p.4-9 / Chapter 4.2.4 --- Comparison to Prior Art --- p.4-10 / Chapter 4.2.5 --- Growth Rate --- p.4-11 / Chapter 4.2.6 --- Energies of Critical Points --- p.4-12 / Chapter Chapter5 --- Conclusions --- p.5-1 / Appendix A Calculation of the actual MO Mass Flow --- p.6-1 / Appendix B Interpretation of in-plane Lattice Parameter --- p.6-3 / Appendix C Structure Factor of Wurtzite Lattice --- p.6-4 / References --- p.7-1

The effect of natural compound AN30 on oral cancer cell line (Ca9-22), and normal oral cell line (HGF-1) was investigated. AN30 was purified from native fern plant Thelypteris torresiana. It had been reported to induce cell cycle arrest, apoptosis and DNA damage, cell growth inhibition in lung cancer cells, breast cancer cells and prostate cancer cells, but the effect in oral cancer is unknown. In a preliminary test, AN30 shows high toxicity to oral cancer cells but not normal oral cells. After treatment of AN30 to oral cancer cells, caspase activation and comet assays were performed to verity apoptosis induction. 2-D electrophoresis was used to find out the differentially expressed proteins between normal and cancer oral cell line under AN30 treatment. The proteins were further identified by LC/MS and western blot. The mechanism of these candidate proteins on drug toxicity remains further investigation.

The microstructure of £b'-Cu6Sn5 during in the early stage of growth was studied. Sn was electroplated onto thin Cu foil at room temperature and the specimen was annealed at 150 ºC for 30 s. The Cu and Sn on the £b'-Cu6Sn5 surfaces were removed electrolytically and the specimens were analyzed with scanning and transmission electron microscopes. The £b'-Cu6Sn5 grains on the Cu side were as small as 5 nm but grew rapidly to 0.3 to 0.5 £gm on the Sn side. The orientation relationships between £b'-Cu6Sn5 and Cu were studied by a thin film technique. Cu was evaporated onto the NaCl (001) and (111) surfaces to form epitaxial Cu thin films and Sn was then evaporated onto the Cu films to form £b'-Cu6Sn5. Two types of orientation relationships were found, i.e., (1) [204]£b'//[001]Cu (zone axis), (40-2)£b'//(110)Cu, and (020)£b'//(1-10)Cu, and (2) [204]£b'//[111]Cu (zone axis), (40-2)£b'// Cu, and (020)£b'//(-1-12)Cu. The interfaces were analyzed. (Chapter 1) A very thin £b-Cu6Sn5 layer was formed by dipping thin Cu foil into molten Sn at 240 ºC for 1 second and quenching in ice water. The Sn and Cu on the £b-Cu6Sn5 surface were removed electrolytically to study the surface morphologies. The £b-Cu6Sn5 grains on the Sn side had a worm-type shape, about 0.3-0.5 £gm wide and up to 2 £gm long, but those on the Cu side were very small, about 5 nm in size. The nucleation and growth of the £b-Cu6Sn5 grains were discussed. The orientation relationships between £b-Cu6Sn5 and Cu were determined by transmission electron microscopy. The (11-20) plane of £b-Cu6Sn5 was found to be the interface with both the Cu (001) and (-111) surfaces, and a common orientation relationship of (0001)£b//(110)Cu was observed. The match of atoms between £b-Cu6Sn5 and Cu on the above interfaces were analyzed. (Chapter 2) A thin film technique was developed to study the orientation relationship and interface between £`-Cu3Sn and Cu by transmission electron microscopy. Epitaxial Cu thin films were grown on the NaCl (001) and (111) surfaces and Sn was evaporated to form £`-Cu3Sn directly without breaking the vacuum. The orientation relationship Z=[001]£`//[111]Cu, (100) £` //(-110)Cu, and (010)£` //(-1-12)Cu was found on the Cu (111) surface, but none on the Cu (001) surface. The interface was analyzed. (Chapter 3) The formation of the Fe-Al inhibition layer in hot-dip galvanizing is a confusing issue for a long time. This work presents a characterization result on the inhibition layer formed on a TiNb-stabilized interstitial-free steel after a short time galvanizing. The Fe-Al and steel interface was free from oxide, so that the Fe-Al intermetallic compound could directly nucleate on ferrite grains. TEM electron diffraction showed that only Fe2Al5 was formed and it had a well-defined orientation relationship of [110]FA// [111]Fe, (001)FA//(0-11)Fe and (1-10)FA//(2-1-1)Fe with Fe substrate where FA stands for Fe2Al5. The interfaces between Fe2Al5 and Fe are discussed. The Fe2Al5 grains nucleated epitaxially on Fe substrate had very small grain size, 20 nm or less, and several variants were intimately mixed. The grains grew rapidly to hundreds of nanometers toward the Zn side. (Chapter 4) The orientation relationships and interfaces of £_-AuSn with the Au (001), (110) and (111) surfaces were studied with transmission electron microscopy. Au was evaporated onto the NaCl (001), (011) and (111) surfaces to form epitaxial Au thin films and Sn was evaporated onto the Au film to form £_-AuSn. Two types of orientation relationships were found: (1) (11-20)£_//(001)Au, (0001)£_//(110)Au, and (1-100)£_//(-110)Au, which was found on the (11-20)£_/(001)Au and the(1-100)£_/(-110)Au interfaces; and (2) (11-20)£_//(-111)Au, (0001)£_//(110)Au, and (1-100)£_//(-11-2)Au, which was found on the (11-20)£_/(-111)Au interface. The interfaces were analyzed by the structures of the surfaces and the orientation relationships. The nucleation of £_-AuSn on these interfaces was also discussed. (Chapter 5)

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

Thesis (M. Phil.)--University of Hong Kong, 2010. / Includes bibliographical references. Also available in print.

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