Collect. Czech. Chem. Commun. 1983, 48, 3307-3314

A new heterocyclic ring closure in ferricyanide oxidation of 2,4,6-triphenylpyridinium salts

Petr Nesvadbaa, Petr Štropa and Josef Kuthanb

a Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6
b Department of Organic Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


The quaternary pyridinium salts Ia-Ic react with alkaline solution of potassium ferricyanide to give the condensed heterocyclic derivatives IIIa, b, IV, whereas the salts Id-If give the pyrrole derivatives IIa-IIc under the same conditions. The diaza heterocycle IIIa reacts with methyl iodide to give methoiodide V, whereas by action of bromine it produces two monobromo derivatives VIa, b. The pyrrole derivatives IIa, b give monobromo derivatives IId, e on bromination. A probable mechanism of formation of the heterocyclic derivatives is discussed.