Catalyst- and metal-free C(sp2)-H bond selenylation of (N-hetero)-arenes using diselenides and trichloroisocyanuric acid at room temperature.

In this paper, we report an eco-friendly approach for the C(sp2)-H bond selenylation of imidazopyridines and other N-heteroarenes as well as simple arenes at ambient temperature. This new protocol consists of the reaction between (N-hetero)-arenes and the diorganyl-diselenides and trichloroisocyanuric acid (TCCA)-ethanol reagent system. In a short reaction time, the desired selenylated products were obtained regioselectively in good yields, with tolerance for a wide range of functional groups.

Versatile Electrochemical Synthesis of Selenylbenzo[b]Furan Derivatives Through the Cyclization of 2-Alkynylphenols.

We report an electrochemical oxidative intramolecular cyclization reaction between 2-alkynylphenol derivatives and different diselenides species to generate a wide variety of substituted-benzo[b]furans. Driven by the galvanostatic electrolysis assembled in an undivided cell, it provided efficient transformation into oxidant-, base-, and metal-free conditions in an open system at room temperature. With satisfactory functional group compatibility, the products were obtained in good to excellent yields.

It takes two to tango: synthesis of cytotoxic quinones containing two redox active centers with potential antitumor activity.

We report the synthesis of 47 new quinone-based derivatives via click chemistry and their subsequent evaluation against cancer cell lines and the control L929 murine fibroblast cell line. These compounds combine two redox centers, such as an ortho-quinone/para-quinone or quinones/selenium with the 1,2,3-triazole nucleus. Several of these compounds present IC50 values below 0.5 µM in cancer cell lines with significantly lower cytotoxicity in the control cell line L929 and good selectivity index. Hence, our study confirms the use of a complete and very diverse range of quinone compounds with potential application against certain cancer cell lines.

Electrohalogenation of organic compounds.

Herein, we present an overview of recent advances in the electrochemical halogenation of organic compounds. Halogen-containing compounds are essential building blocks for post-functionalization in academic research and in different industrial sectors, notably pharmaceutical companies. One of the main advantages of using electrosynthesis is its environmentally-friendly characteristics. Electrosynthesis is recognized as a methodology that can fulfill different criteria of the green chemistry concept and constitutes a promising tool in the development of new procedures in organic synthesis. In this review we target sp, sp2 and sp3 carbon fluorination, chlorination, bromination and iodination reactions using electrolysis as a redox medium. Mechanistic insights and substrate reactivity are also discussed.

Borophosphate glass as an active media for CuO nanoparticle growth: an efficient catalyst for selenylation of oxadiazoles and application in redox reactions.

Herein, we report the preparation of CuO@ borophosphate nanoparticles (CuOnano@glass) and their wide catalytic applications. The glass annealing, under a controlled atmosphere, enables the growth of copper nanoparticles on the glass surface (not within) by an uncommon bottom-up process. Following the thermal annealing of metallic nanoparticles under air atmosphere, supported copper oxide nanoparticles CuONPs on the glass surface can be obtained. The approach enables the glass matrix to be explored as a precursor and a route for the synthesis of supported copper-based nanoparticles in a solvent-free process without immobilization steps or stabilizing agents. In order to demonstrate the wide synthetic utility of this CuONPs glass-based catalyst, one-pot three-component domino reactions were performed under an air atmosphere, affording the desired selenylated oxadiazoles in good to excellent yields. We also extended the application of these new materials as a glass-based catalyst in the phenol hydroxylation and the reduction of 4-nitrophenol.

Electrochemical synthesis of selenyl-dihydrofurans via anodic selenofunctionalization of allyl-naphthol/phenol derivatives and their anti-Alzheimer activity.

Herein, we report an eco-friendly, electrosynthetic approach for the intramolecular oxyselenylation of allyl-naphthol/phenol derivatives. This reaction proceeds with 0.2 equiv. of nBu4NClO4 as an electrolyte and Pt working electrodes in an undivided cell, resulting in the selenyl-dihydrofurans in good to excellent yields. Furthermore, several of the synthesized products presented a high percentage of acetylcholinesterase (AChE) inhibition, highlighting their potential anti-Alzheimer activity.

Photoinduced, Direct C(sp2 )-H Bond Azo Coupling of Imidazoheteroarenes and Imidazoanilines with Aryl Diazonium Salts Catalyzed by Eosin†Y.

Herein, a greener approach to the eosin Y-Na2 catalyzed, C(sp2 )-H bond azo coupling of imidazoheteroarene with aryl diazonium salts is described, under acid free conditions. This direct photoredox process resulted in the corresponding azo products in good to excellent yields. Besides, this new approach could also be applicable to anilines, which is a poorly reactive substrate by other methods. The main features of this reaction are that it provides high yields and is gram-scalable and applicable to biologically relevant imidazoheteroarenes and -anilines.