Chemistry of the aminochromes. Part X. Some further observations on the reactions of aminochromes with thiols

Abstract

The reactions between aminochromes and thiols have been reinvestigated. In general aminochromes react with thiols to give mixtures of products including: 5,6-dihydroxyindoles; thio-substituted 5,6-dill>-droxyindoles (the mercapto residue is no\\ considered to be in the 4-position of the indole nucleus and not the 7-position as previously reported); and relatively unstable addition products formed between the aminochronie and the thiol. The mechanisms by which these conlpounds are formed are discussed. The characterization of three thio-substituted 5,6-dihydroxyindoles by nuclear magnetic resonance spectroscopy is described. The nuclear magnetic resonance spectra of a number of 5,6-diacetoxyindole derivat~vcs are reported.

Novel ultrasensitive and ultrafast voltammetric determination of biological aminochromes on the copper nanodoped mercury monolayer carbon fiber electrode

“…These experiments gave unexpected results considering the thiol's capacity to reduce aminochromes chemically [24]. The studied thiols, at concentrations comparable with those in biofluids, instead of decreasing the analytical signal, their presence increased it by about two orders (Fig.…”

Chemistry of Aminochromes. Part XV. The Reaction of Epinochrome with Thiols

“…The product obtained in this manner was identical to samples of 6-acetoxy-4-S-carboxymethylthio-5-hydroxy-1 -methylindole lactone (1 1) prepared from adrenochrome by the method of Powell c.t al. (5).…”

“…Aminochromes which are substituted in the 3-position by an alkoxyl or hydroxyl group react with thiols to give three types of products: (i) aminochrome/thiol addition products in which the thiol residue is attached to the 3a-position6 of the indole nucleus (l,2), (ii) 5,6-dihydroxyindoles (3,4), and (iii) 4-thiosubstituted 5,6-dihydroxyindoles (5,6). The aminochrome/thiol addition products were the major products formed, at least initially, when the reactions occurred in either neutral or slightly acidic solution, whereas the indolic products predominated at lower p H s .…”