1,2,4,6-Substituted Pyridinium Derivatives-Synthesis and Properties

Abstract

In relation to the investigation of their electrochemical properties we prepared 24 pyridinium derivatives (I, IV, V, VI, VII) with alkyl and aryl substituents in positions 1, 2, 4 and 6, and 19 derivatives with two pyridinium nuclei (II, III, VIII, IX, X) connected by an aliphatic or an aromatic chain. All the compounds were prepared from the corresponding pyrylium derivatives by reacting them with primary amines. The pyrylium derivatives were synthesized by aldolization and acylation followed by cyclization leading to a heteroaromatic pyrylium system. In nucleophilic reactions with amines, the pyrylium derivatives yield pyridinium derivatives. The reaction was performed by adding the corresponding amine to an ethanolic suspension of the starting pyrylium salt.