Electrochemical synthesis of heterocyclic compounds. XII. Anodic oxidation of catechol in the presence of nucleophiles

Abstract

The electrochemical synthesis of coumestan derivatives and some related heterocyclic system (2a‐11a) by anodic oxidation of catechol (1) in the presence of various nucleophiles 2‐11 is described. Products were obtained in good yields and purity. The mechanism of oxidation was deduced from voltammetric data and by coulometry at controlled potential.

Electrochemical synthesis of 6-arylsulfonyl caffeic acid derivatives in aqueous medium

“…1, upon scanning anodically, caffeic acid exhibits one well defined oxidation wave at +0.47 V (vs. Ag/AgCl) corresponding to the formation of corresponding o-benzoquinone derivative which was reduced in the cathodic sweep at +0.27 V vs. Ag/AgCl. Previously [11][12][13][14][15][16][17][18][19] it has been concluded by controlled potential coulometric analysis that the number of electrons involves in the oxidation of catechol and its simple derivatives is two. Therefore, it is reasonable to also assume that the oxidation wave in the CV of caffeic acid corresponds to twoelectron transfer process leading to the corresponding o-benzoquinone.…”

Electrochemical nitration of catechols: Kinetic study by digital simulation of cyclic voltammograms

“…1, curve a). A peak current ratio (I pC 1 /I pA 1 ) of nearly unity which can be considered as a criterion for the stability of o-benenzoquinone produced at the surface of electrode under the experimental conditions [14,[20][21][22][23][24].…”

Mechanistic study of homogeneous reactions coupled with electrochemical oxidation of catechols

“…12). The reaction mechanism includs the oxidation of catechol (1), intermolecular Michael addition reaction and formation of adduct (56), oxidation of adduct (56) and intramolecular Michael addition reaction, respectively (Scheme 19) [59][60][61].…”

“…The oxidation of 59 is easier than the parent-starting molecule (1) by virtue of the presence of negative charge and electrondonating effect of the linked nucleophile. In the next step, the oxidized intermediate (59a) participates in a slow intramolecular Michael addition to form the final product (60). As shown in Fig.…”