Electrochemical behavior of amidine hydrochlorides and amidines

Abstract

The electrochemical behavior of N,N-dimethyl-N′-phenylformamidine hydrochloride was studied on a platinum electrode. The oxidation peak at +0.90 V vs. Ag/Ag+ 0.01 M (in CH3CN −0.1 M LiClO4) was assigned to the oxidation of the chloride anion. N,N-Dimethyl-N′-(4-chlorophenyl)formamidine and N,N-dimethyl-N′-(2-chlorophenyl)formamidine were isolated from the preparative electrolysis of this amidine hydrochloride. The electrochemical behavior of N-phenylbenzamidine hydrochloride and N-phenylcyclohex-3-enecarboxamidine hydrochloride was also studied at platinum and at vitreous carbon. Cyclic voltammetry of a number of amidines was performed. Only N-arylbenzamidines showed a reduction peak at potentials less negative than −3.0 V vs. Ag/Ag+ 0.01 M (discharge potential of the medium at vitreous carbon). Preparative electrooxidations of all amidines studied were unsuccessful because of strong and rapid passivation of the anode. Keywords: amidine, electrochemical oxidation, chloride, amidine hydrochloride.