Electrochemical study of 4-tert-butylcatechol in the presence of 1,3-dimethylbarbituric acid and 13-diethyl-2-thiobarbituric acid.: Application to the electro-organic synthesis of new corresponding spiropyrimidine derivatives

Electrochemical oxidation of 4-tert-butylcatechol (1) has been studied in the presence of 1,3-dimethylbarbituric acid (2a) and 1,3-diethyl-2-thiobarbituric (2b) acid as nucleophiles in aqueous solution, using cyclic voltammetry (CV) and controlled-potential coulometry. The results indicate that the quinone derived from 4-tert-butylcatechol (1) participates in a Michael addition reaction with 2 to form the corresponding 5,5-disubstituted pyrimidine derivatives (5a-5b). In this work, we have proposed a mechanism for the electrode process. The electrochemical synthesis of 5a and 5b has been successfully performed at carbon rod electrodes in an undivided cell in good yield and purity. (C) 2001 Elsevier Science B.V. All rights reserved.