ELECTROCHEMICAL STUDY OF 3,4-DIHYDROXYBENZOIC ACID AND 4-TERT-BUTYLCATECHOL IN THE PRESENCE OF 4-HYDROXYCOUMARIN - APPLICATION TO THE ELECTRO-ORGANIC SYNTHESIS OF COUMESTAN DERIVATIVES

摘要

Electrochemical oxidation of 3,4-dihydroxybenzoic acid (I) and 4-tert-butylcatechol (V) in the presence of 4-hydroxycoumarin (II) as nucleophile in aqueous solution has been studied using cyclic voltammetry and controlled-potential coulometry. The results indicate that I via a 1,4-addition (Michael) reaction under electro-decarboxylation reaction converts to coumestan TV, and V via 1,4-(Michael) and 1,6-addition reactions converts to new coumestan VII. The electrochemical synthesis of IV and VII has been performed successfully in an undivided cell in good yield and purity. (C) 1997 Elsevier Science S.A. [References: 41]