An efficient electrochemical synthesis of diamino-o-benzoquinone: Mechanistic and kinetic evaluation of the reaction of azide ion with o-benzoquinone

Abstract

An efficient method for the synthesis of diamino-o-benzoquinone based on the Michael reaction of electrochemically generated o-benzoquinone with azide ion is described, as well as an estimation of the homogeneous rate constant (k(obs)) of the reaction of o-benzoquinone with azide ion by the digital-simulation method.

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).…”

“…1, curve b) that was enhanced during the repetitive recycling of potential is probably due to 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. [14][15][16][17][18][19][20][21] The overoxidation of 4a was circumvented during the preparative reaction because of the presence of the electron-withdrawing group.…”

“…[14][15][16][17][18][19][20][21] All chemicals were reagent-grade materials. Sodium acetate, solvents and reagents were of pro-analysis.…”

“…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.…”

Synthesis of Diamino Benzoquinones using Facile and One-Pot Chemical Oxidative Method

“…In this respect, as far as our we know, in the past no in situ chemical oxidation reaction of benzoquinones using azide ion (3) has been reported while the electro-oxidation of catechol and hydroquinone with ion azide has been previously reported 11,12 . As stated, this way we have made a facile and one-pot synthesis for diamino benzoquinones available that employs catechols derivatives 3(a-c) or hydroquinone chemical oxidation (1) with azide ion using potassium ferricyanide as an oxidizing agent (Decker oxidation) resulting in high purity and yield.…”