Collect. Czech. Chem. Commun. 1992, 57, 1672-1683

Oxidative and Basic Transformations of Some 1-Heteroaryloligophenylpyridinium Salts. Limitations to the Applicability of Ferricyanide Oxidation

Stanislav Böhma, Richard Kubíka, Jan Němečekb and Josef Kuthana

a Department of Organic Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6
b Institute of Microbiology, Czechoslovak Academy of Sciences, 142 20 Prague


Ferricyanide oxidation of 2,3,4,6-tetraphenyl-1-(2'-pyridyl)pyridinium perchlorate (III) gave, in addition to the biheterocyclic product Ib, two pyrrole derivatives IIb and IIc and in some conditions also the diketone IV. Additional pyrrole derivatives, VII and IX, were obtained analogously from the thiazole 2,4,6-triphenylpyridinium salts V and VIb. Alkalysis of the thiazole salts V and VIb and of the imidazole salts VIc and VId using alcoholic KOH afforded the biheterocyclic products XI-XIV. The mechanisms of the conversions involved are discussed.