A new facile electrochemical method for the synthesis of 4-(pyridine-2-ylthio)benzene-l,2-diols

Electrochemical oxidation of catechols (1a–1c) has been studied in the presence of 2-mercaptopyridine (3) as a nucleophile in water solution using cyclic voltammetry and controlled-potential coulometry. The results revealed that the quinones derived from catechols (1a–1c) participate in Michael addition reaction with 2-mercaptopyridine (3) and converted to the corresponding (pyridine-2-ylthio)benzene-l,2-diol derivatives (4a–4c), via an EC mechanistic pathway. The electrochemical synthesis of compounds 4a–4c has been successfully performed at a carbon rod electrode and in an undivided cell with good yields and high purity.