PMID: 3501464Oct 1, 1987

Electrochemical oxidation of 5-hydroxytryptophan in acid solution

Journal of Pharmaceutical Sciences
K Humphries, G Dryhurst


The electrochemical oxidation of 5-hydroxytryptophan (5-HTPP) in acid solution proceeds by an initial 1e-, 1H+ reaction to a radical intermediate. This radical can dimerize and three diastereomers of 4,4'-bis(5-hydroxytryptophan) have been isolated and characterized. The radical can also undergo further electrochemical oxidation (1e-, 1H+) to a quinoneimine intermediate. Nucleophilic attack by water on this quinoneimine, followed by further oxidation, gives tryptophan-4,5-dione. Nucleophilic attack by 5-HTPP on the quinoneimine gives a dimeric indolenine which undergoes a complex series of chemical and electrochemical reactions leading ultimately to 4-[4-(6-hydroxyquinolyl)]-5-hydroxytryptophan. Two diastereomers of the latter compound have been isolated and characterized.


Oct 1, 1972·Archives of Neurology·R LimS Mullan
Jan 1, 1972·Zeitschrift für Zellforschung und mikroskopische Anatomie·H G Baumgarten, L Lachenmayer
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Apr 1, 1962·The Australian Journal of Experimental Biology and Medical Science·G WOOLLEY, F C COURTICE
Apr 1, 1954·Proceedings of the National Academy of Sciences of the United States of America·D W Woolley, E Shaw


Apr 8, 2004·Toxicology Letters·Yesu T DasHarry G Preuss

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