Graduation date: 1993

In the first part of this thesis, the synthesis, characterization and investigation of ortho-phenyleneethynylenes containing heterocycles, are presented. These compounds display changes in absorption and emission spectra varying with their functionalization and size. These compounds also have the ability to coordinate with metals. The synthesis of coordination compounds and their crystallographic data are reported. The synthesis and characterization of tetraethynyl thiophene compounds containing pyridines are also presented. These compounds exhibit differences in absorption and emission spectra upon exposure to various metal salts. The final topic to be discussed is the synthesis and characterization of diphenyl amine polymers. These polymers could in principle be used in NLO applications or light emitting devices.

abstract / Chemistry / Doctoral / Doctor of Philosophy

The synthesis of 1,2-bis(5-isobenzofuranyl)ethene by two routes is described. The first route involved generation of 1,2-bis(5-isobenzofuranyl)ethene from a bis(acetal) precursor under basic conditions. However, the synthesis was lengthy with low-yielding steps, which led to it being abandoned. The second route involved generation of 1,2-bis(5-isobenzofuranyl)ethene from a bis(oxabicyclic) precursor with 3,6-di(2'-pyridyl)-s-tetrazine. Napththo[1,2-c:5,6-c] difuran and 1,2-bis(5isobenzofuranyl)ethene were used to construct novel cyclophanes by double Diels-Alder reactions with bis(maleimide)s. NMR, AM1 modeling, and X-ray studies of the cyclophanes are discused. Attempts to prepare phenanthro[2,3-c:6,7-c] difuran and its cyclophanes are discussed. None was successful, and investigations were hampered by the inability to obtain sufficient quantities of starting materials. Finally, several suggestions are given for improving the syntheses of 1,2-bis(5- isobenzofuranyl)ethene, phenanthro[2,3-c:6,7-c]difuran, and their cyclophanes. Future directions, such as the functionalization of the double bond of 1,2-bis(5-isobenzofuranyl)ethene, aromatization of the oxabicyclic rings of the cyclophanes, and further X-ray studies are discussed. / x, 122 leaves : ill. ; 28 cm.

This thesis explores three rare synthetic routes: the synthesis of hydrazines via the aza-Lossen rearrangement, the synthesis of carbamoyl azides from amines, and deprotection reactions using water at elevated temperatures. The aza-Lossen reaction was found to be ideal at “infinite dilution” conditions and could be performed with both aryl and alkyl example. Carbamoyl azides could be synthesized in high yields from both aryl and alkyl amines. The carbamoyl azide reaction was found to be much more efficient with Cs (+1) present. Lastly, water at elevated temperatures conditions was efficient at removing various amine and hydroxyl protecting groups.

An extracellular bacteriocin-like substance produced by Clostridium acetobutylicum was detected during studies on an industrial fermentation process. The bacteriocin-like substance was not inducible by either ultraviolet light or mitomycin C, and its production was not associated with the induction of a protease. Studies on the mode of action of the bacteriocin-like substance indicated that it had no significant effect on DNA, RNA, or protein synthesis, and it did not cause the loss of intracellular ATP. However, the bacteriocin-like substance was able to lyse SDS-treated cells and cell walls of C. acetobutylicum and was identified as an autolysin. Some of the characteristics of this extracellular autolysin were determined, and after purification it was shown to be a glycoprotein with a molecular weight of 28 000.

M.Sc. (Chemistry) / Inhibition of mycothiol biosynthesis pathway has attracted attention from chemists and biochemists who aim to develop novel anti-TB drugs. A possible route to inhibit the production of mycothiol in cells may be via the inhibition of enzymes involved in the biosynthetic pathways. Molecular analogues that mimic mycothiol and containing tetrahedral-forming functional groups have been reported to show activity against mycothiol biosynthesis by inhibiting the enzymes in the mycothiol biosynthetic pathway...

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy