On the mechanism of the Tattersall test for morphine
Department of Organic Chemistry, Faculty of Chemistry, National Autonomous University of Mexico, Mexico City (CDMX), Mexico.
Research Article
Magna Scientia Advanced Research and Reviews, 2023, 07(02), 058–061
Article DOI: 10.30574/msarr.2023.7.2.0045
Publication history:
Received on 22 February 2023; revised on 02 April 2023; accepted on 04 April 2023
Abstract:
Being morphine a restricted drug, a rapid colour test for its detection is very useful. Tattersall employed as reagent trisodium ortho-arsenate in sulphuric acid. However, the more common disodiumhydrogen ortho-arsenate heptahydrate can be used also because both salts yield the same reactive species, that is, protonated arsenic acid and a cation with arsenic(IV). An arsenate is formed with the phenolic group in morphine. Dehydration of this organometallic ester yields a cationic intermediate that induces reaction with arsenic acid at ortho-position (electromeric effect), and a concerted mechanism takes place. A dienone is formed and there is elimination of meta-arsenous acid. Aromatization followed by acidolysis of the new arsenate gives water, meta-arsenous acid, and morphine ortho-quinone, via a six-member concerted mechanism. The colours observed in the test are due to halochromism.
Keywords:
Electromeric effect; Meta-arsenous acid; Organic arsenical; Reaction mechanism; Reactive intermediates; Redox reactions; Trisodium arsenat
Full text article in PDF:
Copyright information:
Copyright © 2023 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0