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UBC Theses and Dissertations

I. Preparation of 2- and 4-isobutylphenol and isoamylphenol. II. Quantitative analyses of some polysaccharide gums Merler, Ezio

Abstract

Part I - The work described in this thesis was part of a project to test the possible selective toxicity of some of the secondary alkyl homologues of dinitro-ortho-cresol. The 2-and 4-isobutyl-and isoamylphenols were prepared by an unequivocal synthesis by the method of Klages. Part A describes a Grignard reaction carried out on 2-and 4-methoxybenzaldehyde with isopropylbromide and isobutylbromide respectively. The four carbinols prepared were characterised whenever possible by methoxyl determinations and formation of phenylurethane derivatives, which were analysed for methoxyl and nitrogen values. Dehydration of the carbinols was achieved by refluxing the alcohol with sulphuric acid (20% by weight). The substituted ethylenes were characterised by methoxyl determinations and by formation of nitrosyl chloride derivatives which, were analysed for methoxyl and nitrogen values. The substituted ethylenes were hydrogenated under pressure to give the alkyl anisoles which were characterised by methoxyl determinations and formation of sulphonamide derivatives. The derivatives were analysed for methoxyl and nitrogen values. The alkyl anisoles were demethylated by refluxing with pyridine hydrobromide at 200°C. for five hours. The alkylphenols were characterised by carbon and hydrogen analyses and by formation of 3,5-dinitrobenzoate derivatives. The derivatives were analysed for their nitrogen content. Part B reports the Fries rearrangement of phenylisobutyrate. Isobutyryl chloride was prepared from isobutyric acid. Part of the acid chloride was reacted with phenol to give phenylisobutyrate. A Fries rearrangement of the ester in the absence of solvent at 140°C. gave 2-and 4-hydroxyisobutyrophenone in almost equimolar portions. A low temperature Fries rearrangement of the ester in nitrobenzene solvent gave the 4-hydroxyisobutyrophenone isomer only. A Friedel and Crafts reaction of phenol with isobutyryl chloride using two molar quantities of aluminium chloride in a nitrobenzene solvent gave the two hydroxyisobutyrophenone isomers. The two isomeric hydroxyisobutyrophenones were methylated by using sodium hydroxide and dimethyl sulphate to give 2-and 4-methoxyisobutyrophenone. A Friedel and Crafts reaction of anisole with isobutyryl chloride in carbon disulphide gave 2-and 4-methoxyisobutyrophenone. Oxidation of the two isomeric methoxyisobutyrophenones with potassium permanganate and sodium carbonate gave ortho-and para-methoxybenzoic acid, thus proving the orientation of the substituents. Part II - Mesquite gum, lemon gum, sapote gum A and sapote gum B were analysed quantitatively for their sugar content by a refined step-by-step hydrolytic technique. Standard curves of optical density versus concentration in the submicro scale were experimentally drawn from readings taken on a Beckman D U spectrophotometer on sugar solutions of L-arabinose, D-galactose, L-rhamnose, D-ribose and D-xylose, using a phenol-sulphuric acid method developed by Smith. Synthetic mixtures of L-arabinose, D-galactose, L-rhamnose and D-xylose were separated quantitatively by using paper partition chromatography techniques and were analysed by the above method. Procedure and techniques were thus standardised, Mesquite gum was hydrolysed into its components by N sulphuric acid; the composition of the gum was found to be D-galactose 56.8%, L-arabinose 30.0%, the remaining part representing uronic acid residues. Lemon gum was hydrolysed under controlled acid conditions into the components L-arabinose 22.35% and D-galactose 54.94%, the remaining portion representing uronic acid residues. Similarly sapote gum A was found to be composed of L-arabinose 25.45%, D-xylose 41.62% and uronic acid residues. Lastly sapote gum B was found to be divisible in two portions: a water soluble fraction composed of L-arabinose 25.10%, D-galactose 46.25%, L-rhamnose 6.80%, D-xylose 5.28%, the remaining unaccounted portion representing the uronic acid residues, and a water-insoluble, alkali-soluble fraction composed of L-arabinose 16.27%, D-galactose 25.14%, D-xylose 10.25% and uronic acids.

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