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Title: Studies of a new synthetic route to 3H-indol-3-one 1-N-oxides (isatogens)
Author: Whigham, Brian
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1987
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This thesis is concerned with the investigation of the novel acetic acid-catalysed cyclisation of 1-substituted 2-halogeno-2- (2-nitroaryl)ethanones as a general route to 2-substituted 3//-indol-3-one l-N-oxides (isatogens), a relatively inaccessible class of indole derivatives. The discussion of the results obtained in this investigation is preceded by a survey of the relatively few literature methods for the synthesis of isatogens and also of their chemical reactivity and their biological activity. As a preliminary to the investigation of the scope of the acid- catalysed cyclisation of l-aryl-2-halogeno-2-(2- nitroaryl)ethanones to 2-arylisatogens, methods for the synthesis of the key l-aryl-2-(2-nitroaryl)ethanone starting-material were evaluated. Successful methods employed included, Friedal-Crafts reactions of arenes with 2-nitroarylacetyl chlorides and the triethylamine-catalysed arylation of l-(/VVV- dimethylamino)-2-(2-nitroaryl)ethenes. The former method was found to be more limited than the latter for the synthesis of 1- aryl-2-(2-nitroaryl)ethanones. Bromina-tion of the latter compounds with bromine in 1,2-dimethyoxyethane at room temperature provides a general method for the synthesis of 1- aryl-2-bromo-2-(2-nitroaryl)ethanones. Heating these compounds in glacial acetic acid affords high yields of readily separated mixtures of the corresponding 2-aryl-isatogens and their 5-bromo derivatives. Formation of the latter compounds is largely suppressed when cyclisation is carried out in the presence of hydroquinone. The attempted acid-catalysed cyclisation of ethyl 3-bromo-3-(2-nitrophenyl)-2-oxopropanoate to 2-ethoxycarbonyl isatogen was prevented by difficulties encounted in the synthesis of the bromo-ketoester starting-material.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available