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

Green electro-organic synthesis of a novel catechol derivative based on o-benzoquinone nucleophilic addition

In this work, a green-electrochemical synthesis was applied to catechol oxidation (1) to o-benzoquinone (2) using cyclic voltammetry and potential controlled coulometry.

Electrochemical strategies for C-H functionalization and C-N bond formation

Conventional methods for carrying out carbon-hydrogen functionalization and carbon-nitrogen bond formation are typically conducted at elevated temperatures, and rely on expensive catalysts as well as the use of stoichiometric, and perhaps toxic, oxidants. In this regard, electrochemical synthesis has recently been recognized as a sustainable and scalable strategy for the construction of challenging carbon-carbon and carbon-heteroatom bonds. Here, electrosynthesis has proven to be an environmentally benign, highly effective and versatile platform for achieving a wide range of nonclassical bond disconnections via generation of radical intermediates under mild reaction conditions. This review provides an overview on the use of anodic electrochemical methods for expediting the development of carbon-hydrogen functionalization and carbon-nitrogen bond formation strategies. Emphasis is placed on methodology development and mechanistic insight and aims to provide inspiration for future synthetic applications in the field of electrosynthesis.

Luminescent Metal-Organic-Framework-Based Label-Free Assay of Polyphenol Oxidase with Fluorescent Scan

Metal-organic frameworks (MOFs) are emerging in recent years as a kind of versatile fluorescent sensing materials, but their application to enzyme assays has rarely been studied. Here, the first example of a MOF-based label-free enzyme assay system is reported. A luminescent MOF was synthesized and applied to the activity analysis of polyphenol oxidase (PPO). With its distinct responses to the phenolic substrate and o-quinone product, this MOF could transduce the extent of PPO-catalyzed oxidation to fluorescence signal and enable the real-time monitoring of this reaction. Wide substrate adaptability and high sensitivity (detection limit=0.00012 U mL^-1 ) were exhibited by this method, which meets the requirement of common bioanalysis. Interestingly, by the comparison with molecular capturing reagents, the heterogeneous nature of this MOF-based assay effectively preventing the interaction with the enzyme was proven, thus ensuring the authenticity of results.

Electrochemical synthesis of 1-N-phenyl-4-(sulfonyl)benzene-1,2-diamine derivatives: a mild and regioselective protocol

Regioselective synthesis of 1-N-phenyl-4-(arylsulfonyl)benzene-1,2-diamine derivatives was carried out by the electrochemical oxidation of 2-aminodiphenylamine in aqueous solution in the presence of sulfinic acids as nucleophiles.

Kinetic study of electrochemically induced Michael addition reaction of o-benzoquinone with CH-acid nucleophiles

Electrochemical oxidation of catechol (1) has been studied in the presence of benzoylnitromethane (2a), benzoylacetonitrile (2b), benzoylacetone (2c) and dibenzoylmethane (2d) as nucleophiles in water/acetonitrile (60/40, v/v) solution, by means of cyclic voltammetry and controlled-potential coulometry. The results indicate the participation of electrochemically generated o-benzoquinone (1ox) in the Michael addition reaction with nucleophiles 2a–d, to form the corresponding benzofuran derivatives. Based on the EC mechanism, the observed homogeneous rate constants (kobs ) of the reaction of o-benzoquinone (1ox) with CH-acid nucleophiles (2a–d) were estimated by comparing the experimental cyclic voltammograms with the digitally simulated results. The calculated observed homogeneous rate constants (kobs ) were found to vary in the order 2a > 2b > 2c > 2d.

An Environmentally Friendly Electrochemical Method for Synthesis of Benzofuranoquinone Derivatives

Electrochemical oxidation of catechols (1a-c) has been studied in the presence of 2-hydroxy-1,4-naphtoquinone (3b) in aqueous solutions, using cyclic voltammetry and controlled-potential coulometry. The results indicated that the electrochemically generated o-benzoquinones (2a-c) participate in Michael addition reaction with 3b to the corresponding benzofuranoquinones (8a-c, 10a-c). The electrochemical synthesis of these compounds has been successfully preformed at a carbon rod electrode with good yields using an environmentally friendly method.