Electrochemical methods are more and more widely used for the study of electroactive compounds in pharmaceutical forms and physiological fluids due to their simple, rapid, and economical properties [1]. On the other hand in nature’s collection of biologically active heterocycles, benzofuran derivatives constitute a major group. They are usually important constituents of plant extracts used in traditional medicine and were shown to be effective as antitumor agents, antidepressants, and antihypertensives and even to be cytotoxic [2,3]. To synthesize new benzofuran derivatives we studied the electrochemical oxidation of benzenediols in aqueous solutions and in the presence of a variety of nucleophiles derived from CH acids [4,5]. In the present paper, we describe the preparation of a new benzofuran derivative (5) using electrooxidation of pyrocatechol (1) in the presence of 1-(2-thenoyl)-3,3,3- trifluoracetone (2) as a nucleophile. The results indicate that the o-quinone derived from oxidation of 1,2- dihydroxybenzen (1) participate in Michael addition reactions with 1-(2-thenoyl)-3,3,3-trifluoracetone (2) and via ECEC mechanism convert to the new product, with good yield under controlled potential conditions, at carbon electrode. An additional purpose of this work is to estimate the observed homogeneous rate constants (kobs) of reaction of electrochemically generated o-benzoquinone (1a) with nucleophile (2) by digital simulation of cyclic voltammograms.
