Redoxactive derivatives of the betaine-alkaloid Punicin from Punica granatum. Synthesis and cyclovoltammetry

Hydroquinone- and naphthoquinone-substituted pyridinium, 2,4′-bipyridinium and 4,4′-bipyridinium salts were prepared. These compounds deprotonate to heterocyclic mesomeric betaines in aqueous solution, which can form conjugated or cross-conjugated tautomers. The redox behavior was studied by cyclovoltammetry.