Extrusion of Sulphur

Young, L. B (1962) Extrusion of Sulphur. PhD thesis, University of Glasgow.

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Some 3,6-diaryl-2,7-dihydrothiadiazepines are prepared and converted into 3,6-diarylpyridazines either thermally or by means of N-bromo succinimide in carbon tetrachloride. A dichloro derivative of 2,7-dihydro-3,6-diphenylthiadiazepine, obtained by the action of sulphuryl chloride on the dihydrothiadiazepine, affords 3,6-diphenylpyridazine by treatment with sodium iodide in acetone. The s-dioxides of the dihydrothiadiazepines are more easily converted into pyridazines by thermal means, and in this series of compounds, the oxidised is more easily eliminated than the unoxidised sulphur atom. Oxidation of 3,6-diaryl-2,7-dihydr0thiadiaaepines with hydrogen peroxide in ethanol gave-3,5-diarylpyrazoles. The S-monoxides of the dihydrothiadiazepines are shown to be intermed-iates in the reaction, and other methods are also described for their conversion into 3,5-diarylpyrazoles. 3,5-Diphenylpyrazole is found to be readily degraded by hydrogen peroxide in acetic acid affording 2,5-diphenyl-1-3,4-oxadiazole, dibenzoyl hydrazine and benzoic acid. Attempts to propara 2,7-dihydro-2,3,6,7-tetraphenylthiadi-azepine by reaction of dosyl sulphide with hydrasine gave instead benzylphenyl ketazine and benzil monohydrazene. Desyl sulphone was similarly hydrolysed by hydrazine in ethanol to dibenzyl sulphone. 2,7-Dihydro-3,6-diphenylthiadiazepine-s-dioxide dissolves in cold ethanolic sodium othoxide and gives, on acidification, an unstable solid which forms 3,6-diphenylpyridazine on attempted crystallisation from ethanol. Acidification of the solution obtained by treatment of the s-dioxide with hot ethanolic sodium ethoxide gives a stable solid, Compound A, which is thermally converted into 3-methyl-4,5-diphenylpyrazole with loss of sulphur dioxide. Compound A also affords a methyl sulphone, and structures are suggested for both of these compounds. Repetition of the literature preparation of bis-cyclohexa-nonyl sulphide gave only "bis-cyclohoxanonyl disulphide". This compound is shown to be perhydro-4a,9a-dihydroxythianthren. Dehydration of this diol affords octahydrothianthren which is oxidised to a disulphone. Dehydrogenation of octahydrothianthrea gives thianthren, but octahydrothianthren disulphone resists dehydrogenation under similar conditions. Octahydrothianthren extrudes sulphur to give octahydrodibensothiophen in high yield. Oxidation of octahydrodibenzothiophen gives tetrahydrodibenzo- thiophen sulphone, which is reduced to tetrahydrodibenzothiophen by lithium aluminium hydride. Octahydrodibenzothiophen is readily dehydrogenated to dibenzothiophen, but tetrahydrodibenzothio-phen sulphone resists similar dehydrogenation conditions. Cleavage of perhydro-4a,9a-dihydroxythianthren by potassium hydroxide in dimethylformamide, and reaction with phenacyl bromide gives cyclohexanonylphenacyl sulphide. By reaction with hydrazine, this sulphide condenses to the corresponding dihydrothiadiaz-epine, which decomposes, in boiling ethylene glycol, to 3-phenyl-tetrahydrocinnoline. The major peaks in the infrared spectra of a number of pyrazsies and their N-acetyl derivatives are recorded, similarities are observed, and the existence of a characteristic frequency of absorption of the pyrazole nucleus is suggested.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Organic chemistry
Date of Award: 1962
Depositing User: Enlighten Team
Unique ID: glathesis:1962-79450
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 05 Mar 2020 09:32
Last Modified: 05 Mar 2020 09:32
URI: https://theses.gla.ac.uk/id/eprint/79450

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