Electrosynthesis of hydroquinonethioethers using electrochemical oxidation of hydroquinone in the presence of thiouracil derivatives

Electrochemical oxidation of hydroquinone (1a) has been studied in the presence of 6-methyl-2- thiouracil (3a) and 6-propyl-2-thiouracil (3b) as nucleophiles in a DMF/buffer mixture, using cyclic voltammetry and controlled-potential coulometry. The results indicated that the p-quinone (2a) derived from 1a participates in a 1,4-Michael addition reaction with the thiouracil derivatives (3a-b) to form the corresponding hydroquinonethioether derivatives (6a-6b). The electrosynthesis of these compounds (6a-b) has been successfully performed on carbon rod electrodes in an undivided cell in good yield and purity.