Vicinal π Interactions in the Electrochemical Oxidation of a Carboxylic Acid

Cyclic voltammetry of 5-carboxy-1,3-diphenyl-5-methyl-2-pyrazoline in acetonitrile reveals the presence a small peak at ca. 0.5 V lower overpotential than the usual peak position for diphenylpyrazolines. The peak is due to the anion form produced in the double layer and is attributed to the presence of through space interactions between the pyrazoline π system and the carboxylate group. The anodic oxidation reaction proceeds with decarboxylation to produce the aromatized pyrazole. © 1977, American Chemical Society. All rights reserved.