Thesis (M. Phil.)--University of Hong Kong, 1981.

Thesis (M. Phil.)--University of Hong Kong, 1982.

Thesis (M. Sc.)--York University, 2001. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references (leaves 78-82). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ71605.

published_or_final_version / Chemistry / Master / Master of Philosophy

published_or_final_version / Chemistry / Master / Master of Philosophy

No description available.

Inaug.-diss.--Technische hochschule "Fridericiana" Karlsruhe.

Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 81-83).

PART I A synthetic sequence leading to new and inaccessible 3,4-,5-trialkylated pyridines has been developed 3,4-Dimethyl-5-cyanopyridine was converted to 3,4-dimethyl-5-acetylpyridine on treatment with methylmagnesium iodide and the acetylpyridine was subsequently treated with ethylmagnesium iodide to yield 3,4-dimethyl-5(2-hydroxy-2-butyl)pyridine. Removal of the hydroxyl group was accomplished by means of red phosphorus and hydriodic acid and the resulting olefinic compounds were catalytically hydrogenated to 3,4-dimethyl-5-s-butylpyridine. For further studies in this area, 3,4-dimethyl-5-acetylpyridine was reduced to 3,4-dimethyl-5-ethylpyridine by the Wolff-Kishner reaction and the latter was condensed with benzaldehyde to afford 3-methyl-4-styryl-5-ethyl-pyridine. This, on ozonolysis, was converted to 3-methyl-5-ethyl isonicotinic acid which was subsequently methylated with diazomethane to methyl 3-methyl-5-ethyl-4-pyridine-carboxylate. The nature of the synthesis allows the preparation of virtually any type of 3,4-,5-trialkylated pyridine by straightforward variations at the appropriate stage. PART II In relation to Part I, the synthesis of 3,5-dimethyl-4-substituted pyridines was undertaken. 3,5-Lutidine was reacted with acetic anhydride and zinc to afford in good yield the unexpected 3,5-dimethyl-4-acetyl-pyridine. This was then conveniently converted to 3,5-dimethyl-5-ethylpyridine on reduction with acetic acid and zinc thereby confirming the structure of the acetylpyridine. The acetylpyridine was also reduced with lithium aluminum hydride to 3,5-dimethyl-4-(1-hydroxyethyl)pyridine which in turn was readily dehydrated with phosphorus pentoxide to 3,5-dimethyl-4-vinylpyridine. Both the hydroxypyridine and the vinylpyridine on treatment with hydrobromic acid yielded 3,5-dimethyl-4(2-bromoethyl)-pyridine hydrobromide. This was then converted to 3,5-dimethyl-4-(2-cyanoethyl)pyridine. The preparation of these compounds was possible due to the utilization of the steric effects enforced by the two neighbouring methyl groups at the 3 and 5 positions of the pyridine ring. This sequence of reactions provides a valuable method by which 3,5-dimethyl-4-substituted pyridines can be synthesized owing to the availability of the starting material and to the relatively high yielding reactions. / Science, Faculty of / Chemistry, Department of / Graduate

Pyridine salts were investigated as acids in the pyridine system. The mono and the dihydrochloride salts were found to be the best dissolving reagents for the metals and the sulphides used. Pyridine hydrochloride was most effective in the molten state, whereas pyridine dihydrochloride was found to be quite reactive at room temperature when dissolved in a chloroform solution. Side reactions were investigated and were found to occur only with Mg, Al, and Zn with molten pyridinium chloride. The complex salts, (C₅H₅N.H)₂[MnCl₅]C₅H₅N and (C₅H₅N.H)HgCl₄ were isolated and investigated. / Science, Faculty of / Chemistry, Department of / Graduate