A Facile Electrochemical Method for Synthesis of New Benzofuran Derivatives

Abstract

Electrooxidation of 3-substituted catechols has been studied in the presence of dimedone in aqueous solution, using cyclic voltammetry and controlled-potential coulometry. The results indicate that the quinones derived from catechols participate in Michael addition reactions with dimedone to form the corresponding benzofuran derivatives (6a-c). We propose a mechanism for the electrode process. The efficient electrochemical synthesis of 6a-c has been performed at carbon rod electrodes in an undivided cell using a constant current.

Electrochemical Synthesis of 4-(Dihydroxyphenylthio)-2H-chromen-2-one Derivatives

“…These peaks are correspond to the oxidation of catechol (1a) to o-benzoquinone (2a) and vice versa within a quasi-reversible two electron process. [14][15][16][17][18][19][20][21] The oxidation of catechol (1a) in the presence of 4-mercaptocoumarin (3) as a nucleophile was studied in some details. for a 1 mM solution of 1a in the presence of 1 mM of 4-mercaptocoumarin (3).…”

“…12,13) A literature survey reveals that, in contrast to the widely studied, coumarin derivatives, no paper has reported the synthesis of 4-(dihydroxyphenylthio)-2H-chromen-2-one derivatives. Following our experiences in electrochemical oxidation of catechols in the presence of nucleophiles, [14][15][16][17][18][19][20][21] we envisaged that synthesis of organic compounds with both structures of catechol and coumarin might cause an enhancement of pharmaceutical properties and medicinal activities. This idea prompted us to investigate the electrochemical oxidation of catechols in the presence of 4-mercaptocoumarin as the nucleophile and we have discovered an easy and one-pot electrochemical method for the synthesis of 4-(dihydroxyphenylthio)-2H-chromen-2-one derivatives (4a-d) in high yield and purity, using this environmentally friendly method with high atom economy.…”

Clean and Green Synthesis of New Benzothiazole Derivatives via Electrochemical Oxidation of Catechol Derivatives

“…The anodic peak (A1) shifts to positive potentials and the cathodic peak (C1) shifts to negative potentials, in the presence of 3a and 3b ( Figure 1, curves b and c), are probably because of the formation of a thin film of product at the surface of the electrode, inhibiting, to a certain extent, the performance of the electrode process. 15 The voltammograms of 3a and 3b…”

“…Chem. Acta 2016, 89(1), [7][8][9][10][11][12][13][14][15] in the absence of 1a are shown in Figure 1, curves d and e. These compounds are electrochemically inactive in the range of the potential studied. In addition the cyclic voltammogram of isolated and purified product 6a was recorded under the same conditions but in DMF media (not soluble in water/DMF mixture).…”

“…Chem. Acta 2016, 89(1), [7][8][9][10][11][12][13][14][15] same electrodes as undivided cell with a fine glass frit sep arator. The anolyte was the reaction mixture with composition same as that was used in previous experiment (undivided cell).…”