Photo-/electrochemical catalyzed oxidative R 1 -H/R 2 -H cross-coupling with hydrogen evolution has become an increasingly important issue for molecular synthesis. The dream of construction of C−C/C−X bonds from readily available C− H/X−H with release of H 2 can be facilely achieved without external chemical oxidants, providing a greener model for chemical bond formation. Given the great influence of these reactions in organic chemistry, we give a summary of the state of the art in oxidative R 1 -H/R 2 -H cross-coupling with hydrogen evolution via photo/electrochemistry, and we hope this review will stimulate the development of a greener synthetic strategy in the near future.

The dearomatization of arenes represents a powerful synthetic methodology to provide three-dimensional chemicals of high added value. Here we report a general and practical protocol for regioselective dearomative annulation of indole and benzofuran derivatives in an electrochemical way. Under undivided electrolytic conditions, a series of highly functionalized five to eight-membered heterocycle-2,3-fused indolines and dihydrobenzofurans, which are typically unattainable under thermal conditions, can be successfully accessed in high yield with excellent regio-and stereo-selectivity. This transformation can also tolerate a wide range of functional groups and achieve good efficiency in large-scale synthesis under oxidant-free conditions. In addition, cyclic voltammetry, electron paramagnetic resonance (EPR) and kinetic studies indicate that the dehydrogenative dearomatization annulations arise from the anodic oxidation of indole into indole radical cation, and this process is the ratedetermining step.

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International audienceThe regioselective 2- or 5-arylation of imidazole derivatives with aryl halides using palladium catalysts has been described in recent years; whereas the arylation at both C2 and C5 carbons of imidazoles in high yields has not been performed. We found conditions allowing the access to these 2,5-diarylimidazoles via a one pot reaction. The choice of the base was found to be crucial to obtain these products in high yields. Using CsOAc as the base, DMA as the solvent and only 2 mol % of the phosphine-free Pd(OAc)2 the catalyst, the target 2,5-diarylated imidazoles were obtained in moderate to good yields with a wide variety of aryl bromides. Substituents such as fluoro, trifluoromethyl, formyl, acetyl, propionyl, ester, nitro or nitrile on the aryl bromide were tolerated. Sterically congested aryl bromides or heteroaryl bromides can also be employed. Surprisingly the nature of the substituent at position 1 on the imidazole derivative exhibits a huge influence on the reaction

Thirty-four imidazole-based compounds synthesized by one-pot catalytic method were evaluated for their antifungal and antibacterial activities against several fungal and bacterial strains. None of the compounds had antibacterial activity. Interestingly, compounds 1 , 2 , 3 , 10 and 15 displayed a strong antifungal activity against all the tested fungal species, while compounds 5 , 7 , 9 , 11 , 21 and 27 showed a moderate antifungal activity. To better understand the biological activity of the most active compounds ADME–Tox and molecular docking studies were carried out. Interestingly, compounds 1 , 2 , 3 , 7 , 10 and 15 showed excellent bioavailability. In addition, compounds 1 , 2 and 3 , exhibited good toxicity profiles. Docking studies of the two most active compounds 2 (IC 50 of 95 ± 7.07 μM) and 10 (IC 50 of 235 ± 7.07 μM) suggested that they might act by inhibiting the fungal lanosterol 14α-demethylase. Therefore, these novel antifungal agents merit further characterization for the development of new antifungal therapeutics. Electronic supplementary material The online version of this article (10.1186/s13065-019-0623-6) contains supplementary material, which is available to authorized users.

Direct electrochemical oxidative functionalization of caffeine under metal‐free and external‐oxidant‐free conditions was achieved. Nucleophiles such as various substituted pyrazoles, alcohols, and sodium trifluoromethanesulfonate can be utilized with high diastereoselectivity for the dearomatizative functionalization of caffeine. In addition, selective C2 functionalization of caffeine has also been realized with the modification of solvent and reaction time. A gram‐scale experiment demonstrates the potential application in the derivatization of caffeine.

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A new library of N,N,N',N' -tetradentate pyrazoly compounds containing a pyrazole moiety was synthesized by the condensation of (3,5-dimethyl-1H-pyrazol-1-yl)methanol 2a or (1H-pyrazol-1-yl)methanol 2b with a series of primary diamines in refluxed acetonitrile for 6h. The antifungal activity against the budding yeast Saccharomyces cerevisiae, as well as the antibacterial activity against Escherichia coli of these new tetradentate ligands were studied. We found that these tetradentate ligands act specifically as antifungal agents and lack antibacterial activity. Their biological activities depend on the nature of the structure of the compounds.