Green electro-organic synthesis of a novel catechol derivative based on o-benzoquinone nucleophilic addition

Abstract

In this work, a green-electrochemical synthesis was applied to catechol oxidation (1) to o-benzoquinone (2) using cyclic voltammetry and potential controlled coulometry. Encouraging results were obtained in the presence of semicarbazide (3) as a nucleophile in an ethanol/phosphate buffer mixture (pH 7.0). The pH, number of cycles, and scan rate were studied. The results indicate that the generated o-benzoquinone (2) participates in a Michael addition reaction with nucleophilic hydrazide via the ECEC mechanism to form a new triazinone adduct. The obtained results showed that a novel heterocyclic triazinone (9) product functionalized with hydroxyl and amide groups had been synthesized with a 68% yield. After purification, the product has been characterized by IR, UV-visible, GC/MS, ¹H, and ¹³C NMR. The green-electrochemical synthesis approach produced novel organics with excellent purities and yields while being environmentally friendly and free of hazardous reagents.