A study of the oxidation of some phenolic amines

Hamblin, MR, 1976. A study of the oxidation of some phenolic amines. PhD, Nottingham Trent University.

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Abstract

The synthesis of nitrogen- and oxygen- containing spirodienones by the oxidation of amino- or hydroxy- substituted diphenylamines 'has been investigated. Preliminary attempts to prepare 2,4'- dihydroxy-N-acyl- (or N-tosyl)- diphenylamines by established methods gave poor results, but 2,4'-dialkoxy-N-tosyldiphenylamines were readily obtained from the reaction of aryl bromides with secondary sulphonamides under Ullmann conditions. The scope and limitation of this novel synthetic approach to a wide range of symmetrically and un symmetrically substituted N-tosyl diphenylamines were explored, and among the terptiary sulphonamides thus accessible were N-2-aminophenyl-N-4-hydroxyphenyltoluene-4-sulphonamide, and a range of derivatives containing substituents on the amino group.

Oxidation of diphenolic and aminophenolic diphenylamine derivatives was investigated, and three spiroheterocycles containing novel ring systems were obtained; in the systems studied, the secondary toluene-4-sulphonamido group was found to undergo oxidative cyclisation as readily as a phenolic hydroxyl. The reaction of two of the dienones with methylmagnesium iodide gave anomalous products consistent with 1,3-addition of the Grignard reagent to the dienone carbonyl group.

Following publication of a report on anodic oxidations, a range of phenolic tetrahydroisoquinoline-1-carboxylic acids was prepared and found to undergo oxidative decarboxylation to dihydroisoquinolines when treated with enzymes known to oxidise phenols, namely fungal laccase and horseradish peroxidase. The enzyme parameters (Km and V) for these reactions were determined. This reaction is additional evidence of the Hahn proposal for the biogenesis of isoquinoline alkaloids 8Jid also suggests that useful parallels maybe drawn between enzymatic and electrochemical investigations.

7-0-Benzyl-2-formylcoclaurine was synthesised and subjected to controlled potential anodic oxidation, A product different from starting material was isolated but it could not be obtained completely pure.

Item Type:	Thesis
Creators:	Hamblin, M.R.
Date:	1976
ISBN:	9781369324891
Identifiers:	Number Type PQ10290240 Other
Divisions:	Schools > School of Science and Technology
Record created by:	Laura Ward
Date Added:	24 Jun 2021 09:19
Last Modified:	26 Oct 2023 08:27
URI:	https://irep.ntu.ac.uk/id/eprint/43180

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