Electrolysis of A -heterocyclic compounds

Sec. III.A] ELECTROLYSIS OF N-HETEROCYCLIC COMPOUNDS 4. Formation of Nitrogen-Nitrogen Bonds... 

The review on the electrolysis of JV-heterocyclic compounds by Lund in 1970 included a discussion on the polarographic behavior of quinazoline. The reduction of quinazoline was complicated by covalent hydration in acidic solution, because the hydrated species were not easily reduced. The anhydrous species in alkaline medium were reduced stepwise to dihydro and then to tetrahydroquinazoline, and the dihydro radical intermediate was capable of dimerization. The protonation rates of N-heterocycles in aqueous solution could be determined by polarographic techniques. The rates for quinazoline, and pyrimidine, however, were too fast for measurement which was consistent with predictions from quantum-chemical calculations. ... 

Phenyl radicals can be generated by the thermal decomposition of lead tctrabcnzoate, phenyl iodosobenzoate, and diphenyliodonium hydroxide,- - and by the electrolysis of benzoic acid.- These methods have been employed in the arylation of aromatic compounds, including heterocycles. A method of promise which has not been applied to the arylation of heterocycles is the formation of aryl radicals by the photolysis of aromatic iodides at 2537... 

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