A. Napolitano, M. d’Ischia, G. Prota
1989
Citations
0
Influential Citations
11
Citations
Journal
Tetrahedron
Abstract
Abstract Oxidation of 4-, 6- and 7-hydroxyindoles with sodium periodate in phosphate buffer at pH 7.0 leads to complex mixtures of oligomeric products, the majority of which have beenisolated and characterised as the O-acetyl derivatives.7-Hydroxyindole (6) gives predominantly the dimers 9 and 10 as well as the trimer 11 and the tetramer 12 in smaller amounts. The 4- and 6-hydroxy isomers 7 and 8 follow less clear-cutreaction paths, characterised by the formation of the oligomers13-16 and 17-19 respectively, along with polymeric materials. The observed mode of polymerisation of hydroxyindoles 6-8 isapparently consistent with a mechanism involving nucleophilicaddition of the starting indoles to the electrophilic positions of transient quinonimine or phenoxonium-like intermediates.