Anodic Oxidation of N,N-diethyl-p-phenylenediamine in the Presence of Thiobarbituric Acid: Electrochemical Synthesis, Mechanistic Study and DFT Calculations

Due to the wide range of pharmacological and biological properties of thiobarbiturates, a great effort has been devoted to the synthesis of the thiobarbituric acid derivatives. In this work, the electrochemical oxidation of N,N-diethyl-p-phenylenediamine has been studied in the presence of thiobarbituric acid as the nucleophile in aqueous solutions, using cyclic voltammetry and controlled-potential coulometry. The results indicate that the electrochemically generated diimine participates in a Michael-type addition reaction with thiobarbituric acid and via an ECE mechanism converts to the product. In this work, the new thiobarbituric acid derivative is provided with high yield, without reagents and catalyst at a carbon electrode. Density Functional Theory (DFT) calculations were used to confirm the structure of the product and simulate the HNMR and CNMR spectra.