Electrochemical Synthesis of 5-Purin-6'-ylthiocatechols in Aqueous Medium

The electrochemical synthesis of 5‐purin‐6′‐ylthiocatechols was carried out by anodic oxidation of catechol derivatives 1a–1d in the presence of 6‐mercaptopurine (2) in aqueous solution. Results of cyclic voltammetry and controlled‐potential electrolysis indicated that the starting catechols were first oxidized to the corresponding o‐benzoquinone, which underwent further Michael addition with 6‐mercaptopurine to produce titled products 3a–3d following an EC (E=electrochemical and C=chemical step) mechanism. Such work further demonstrates the versatility of the anodic oxidation of catechols and their in‐situ transformation for the synthesis of derivatized catechols.