Synthesis of 3-aryl-2-arylamidobenzofurans based on the Curtius rearrangement

The synthesis of novel 3-aryl-2-arylamidobenzofurans has been accomplished via a Curtius rearrangement strategy in four steps from benzofuran-2-carboxylic acids. The requisite Suzuki-Miyaura cross-coupling, with benzyl 3-bromobenzofuran-2-ylcarbamate or 2-arylamido-3-bromobenzofurans, revealed an unusual reductive debromination process due to the presence of the free NH group. This dehalogenation can be suppressed by N-alkylation. DMAP is an efficient reagent for the one-pot conversion of benzyl benzofuran-2-ylcarbamates into the corresponding benzofuran-2-arylamides through aroylation, thus acting both as an acyl transfer reagent and a deprotecting agent of the Cbz group. A mechanism is postulated.     

A Fast and Direct Amperometric Determination of Hg2+ by a Bienzyme Electrode Based on the Competitive Activities of Glucose Oxidase and Laccase

A new concept of enzyme inhibition‐based biosensor involving the appearance of an amperometric signal for an inhibition by mercury was developed. The bienzyme sensor was composed of two layers of clay materials. The inner layer was constituted of layered double hydroxides entrapping laccase wired by ABTS. The outer laponite layer contained glucose oxidase (GOD). GOD catalyzed the glucose oxidation with the reduction of O₂ into H₂O₂. This induced a drastic decrease of the biosensor response to O₂ by the electrically wired laccase. HgCl₂ inhibited the O₂ consumption by GOD leading to a signal increase of the electroenzymatic reduction of O₂.     

Novel Synthetic Approach towards Amino-Substituted Polycyclic Aromatic Hydrocarbons through Electrocyclization of Keteniminium Salts

Polycyclic aromatic hydrocarbons (PAHs) are an important family of molecules in science and technology. Amino-substituted PAHs are promising building blocks to create attractive molecules for materials science. However, the synthetic limitations have hampered to produce diverse structures of amino-substituted PAHs. Here we describe a novel efficient synthetic method to access amino-substituted PAHs through the electrocyclization of highly reactive keteniminium species. We demonstrated the synthesis of various amino-substituted PAHs and disclosed some of their photophysical properties. Furthermore, combination with theoretical calculation revealed that the multiple electrocyclization reactions of keteniminium species is a stepwise process and the fusion of additional aromatic ring to the substrate accelerates the electrocyclization.