Electrochemical study of catechols in the presence of 4,6-dihydroxy-2-methylpyrimidine

Electrochemical oxidation of catechol (1a), 3-methylcatechol (1b), and 3-methoxycatechol (1c) has been studied in the presence of 4,6-dihydroxy-2-methylpyrimidine (3) as a nucleophile in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the quinones derived from catechols (1a–1c) participate in Michael addition reactions with 3 to form the corresponding benzofuro[2,3-d]pyrimidine derivatives (6a–6c). The electrochemical synthesis of (6a–6c) has been successfully performed in an undivided cell in good yield and purity. The mechanism of oxidation was deduced from voltammetric data and by coulometry at controlled-potential. The products have been characterized after purification by IR, 1H NMR, 13C NMR and MS.