Thesis (Ph. D.)--University of Chicago, 1920. / "Private edition, distributed by the University of Chicago libraries." Published by Jean F. Piccard and Louis M. Larsen in the Journal of the American chemical society, [pt.] I in v. 39, 2006-2009 (1917) [pt.] II in v. 40, 1079-1092 (1918). Also available on the Internet.

Thesis (Ph. D.)--University of Pennsylvania, 1916. / "Reprinted from the Journal of Biological Chemistry, vol. XXVI, no. 1, 1916." Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, 1920. / "Private edition, distributed by the University of Chicago libraries." Published by Jean F. Piccard and Louis M. Larsen in the Journal of the American chemical society, [pt.] I in v. 39, 2006-2009 (1917) [pt.] II in v. 40, 1079-1092 (1918).

Thesis (Ph. D.)--Columbia University, 1921. / Vita.

Thesis (Ph. D.)--Columbia University, 1933. / Vita. Bibliography: p. 47.

Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.) - University of St Andrews, April 2010.

A novel preparative method has been discovered in our laboratories which produces hydroxy-substituted phenolic ethers in a simple one-pot process. Initially it was found that 4-hydroxyacetophenone, when oxidized in the presence of ammonium peroxydisulfate and concentrated sulfuric acid in methanol, resulted in 4- methoxyphenol as product in high yield. Being novel, no information about the method was available in the literature, and hence it was our task to study the reaction more extensively. The scope of the reaction was investigated in that different reagents and substrates, as well as alternative oxidants, catalysts and alcohols (or reagents which may be envisaged to behave similarly to alcohols) were used. The studies showed that 4- hydroxy-substituted benzaldehyde and acetophenone, vanillin, fuchsones and stilbenequinones as substrates all successfully afforded the phenolic ether. Other oxidants such as hydrogen peroxide, sodium perborate etc. also afforded the phenolic ether but were less effective. The use of other acids than sulfuric acid resulted in comparable or lower yields of the desired phenolic ether. When the use of alcohols or similar reagents was varied, it was found that methanol, ethanol, benzyl alcohol, allyl alcohol, but-3-en-1-ol, hex-5-en-1-ol and undec-10-en-1-ol all afforded the desired ethers in significant yields. In an investigation to determine how this method may be useful for industrial applications, it was observed that compounds such as 3,5-di-tert-butyl-4-hydroxysubstituted alkenyloxy phenols, having potential application as antioxidant precursors in the polymer industry, may be prepared. Results showed that the reaction became less efficient when the alkenyl chain length was increased. The use of different acids and oxidants, the change of the oxidant:substrate ratio and the addition of a potential lanthanide catalyst did not improve the yield of the desired ether. A mechanism for the reaction was proposed which involved an initial Baeyer-Villiger oxygen insertion step to afford an ester which was hydrolysed in situ to hydroquinone. The remaining oxidant was then involved in oxidizing some of the soformed hydroquinone to benzoquinone. It was then proposed that these two compounds, i.e., hydroquinone and benzoquinone, interacted with each other in solution, forming a charge-transfer complex. According to our proposal, the carbonyl group of the benzoquinone, when complexed with hydroquinone in solution, was then attacked by nucleophilic reagents such as alcohols. Etherification hence resulted as a consequence of this attack. A statistical experimental evaluation and optimization study was then performed which led to a system that produced the phenolic ether, 4-methoxyphenol, in an 86% yield. An analysis of the effects of the reaction parameters on the reaction showed that the reaction temperature and the oxidant:substrate ratio played a major role in deciding the effectiveness of the reaction, while the amount of substrate and acidic catalyst had a much smaller influence on the ether yields.

No description available.

Several epidemiological studies .have demonstrated the importance of diet in the development of gastro-intestinal carcinomas in man. This study examines the role of plant phenolics, major components of the human diet. Employing a CHO cell test system, it was observed that phenolics with at least two hydroxyl groups in the ortho position, relative to each other were particularly clastogenic. This activity was abolished by the addition of S9, a rat liver microsomal preparation. The clastogenic activity of these compounds was found to increase with time, alkaline pH, and the presence of transition metals. It was therefore deduced that the source of activity might be an oxidative by-product. High' pressure liquid chromatography was used to separate out these oxidative products. No activity was found to reside in any of the separated components or combinations of components. Further study therefore centred on oxidative products not retained by chromatography and on those labile to this.process. Under oxidative conditions, the presence of hydrogen peroxide was detected. Levels measured were sufficient to explain the clastogenic activity of completely oxidized solutions of phenolic acids. Addition of the enzyme, catalase, appeared to abolish all activity of completely oxidized solutions. Hydrogen peroxide could not, however, account for the genotoxic effects measured in freshly prepared solutions. The presence of superoxide was detected in actively oxidizing solutions of plant phenolics. Its production appeared to be pH-dependent. Addition of superoxide dismutase increased the clastogenic activity of compounds tested, presumably by converting superoxide to peroxide, a more stable oxidative by-product. Addition of tyrosinase, a monophenol oxidase, also increased the clastogenic activity of freshly prepared solutions. Since this enzyme catalyzes the oxidation of several phenolics without subsequent generation of peroxide, it was deduced that phenolic free radicals must also be present which could be at least partially responsible for the enhanced biological activity. Electron spin resonance proved this was the case. Using electron spin resonance, the primary oxidative products were characterized both at high pH and by enzymatic activation. The results obtained agree with those published in the literature. Several reports in the literature have suggested that phenolics may also act as free radical scavengers. The importance of plant phenolics in diet may therefore depend on the oxidative conditions of the system to be tested. Under oxidative conditions, free radicals appear to be generated, which are capable of causing mutations and chromosomal rearrangements. Phenolic oxidation products may therefore play a role as initiators and promotors of carcinogenesis. However, under alternate conditions, phenolics may also act to scavenge free radicals, and could therefore be classed as inhibitors of carcinogenesis. / Science, Faculty of / Zoology, Department of / Graduate