Diels-Alder reaction between indoles and cyclohexadienes photocatalyzed by a (thia)pyrylium salt

"Thiapyrylium salt 1 is an efficient photocatalyst in the Diels-Alder reaction between indoles (InHs) and 1,3-cyclohexadienes (CHDs). For instance, irradiation of deaerated dichloromethane solutions containing 1 (1 mM), indole (20 mM) and cyclohexadiene (40 mM), in the presence of an acylating agent, led to the Diels-Alder cycloadduct in 62% yield (endo:exo ratio of 1.8:1). Taking into account the very high intersystem crossing yield (Φisc = 0.97) of thiapyrylium salt 1, involvement of its triplet excited state in this Diels-Alder reaction has been studied using steadystate and time-resolved experiments; the results are compared with those previously obtained for pyrylium salts, which exhibit a considerable fluorescence quantum yield and are assumed to operate via electron transfer from the InH to their singlet excited state."Gonzalez Bejar, Maria, [email protected] ; Stiriba, Salah Eddine, [email protected] ; Perez Prieto, Julia, [email protected]

Sustainable Construction of Heterocyclic 1,2,3-Triazoles by Strict Click [3+2] Cycloaddition Reactions Between Azides and Alkynes on Copper/Carbon in Water

1,4-Disubstituted-1,2,3-triazoles, considered as an important and useful class of heterocycles with potential applications in material science and biology, have been prepared in an efficient and selective manner by copper on carbon-catalyzed [3+2] cycloaddition reactions of azides and alkynes (CuAAC) in water under strict click chemistry conditions. Copper(I) catalysts heterogenized onto commercially activated carbon materials (Cu-CC) and on another carbon material produced from vegetable biomass using Argan nut shells (Cu-CANS) were found to be versatile catalytic sources for sustainable CuAAC. These copper on carbon supports were prepared and fully characterized by using two types of activated carbons that exhibit different porosity and specific surface. The delineation of the nature of the catalytic copper species and the role of the carbon support in the CuAAC were addressed. These heterogeneous copper on carbon catalysts were recovered and reused until ten catalytic runs without any noticeable loss of activity

Synergistic assembly of hyperbranched polyethylenimine and fatty acids leading to unusual supramolecular nanocapsules

Self-assembly of hyperbranched polyethylenimine (PEI) and fatty acids leads to supramolecular inverted micellar structures that are able to irreversibly transfer water-soluble guest molecules into organic solvents.Perez Prieto, Julia, [email protected] ; Stiriba, Salah Eddine, [email protected]

Click synthesis, anticancer activity, and molecular docking investigation of some functional 1,2,3-triazole derivatives

1,2,3-triazole skeleton is a privileged building block for the discovery of new promising anticancer agents. In this report, new 1,4-disubstituted 1,2,3-triazoles with the bioisoster triazole moiety were straightforwardly prepared under copper-catalyzed azide-alkyne [3+2] cycloaddition reactions (CuAAC) regime using a variety of both functional organic azides and terminal alkynes. The resulting functional 1,4-disubstituted 1,2,3-triazole compounds were fully characterized and subsequently tested for their antiproliferative activity against four different cancer cell lines. The cytotoxicity tests carried out with these 1,2,3-triazole derivatives show average IC50 values ranging from 15 to 50 μM by comparison with the standard reference drug, namely doxorubicin. The phosphonate 1,2,3-triazole derivative was found to exhibit the best antiproliferative activity among the studied compounds against the HT-1080 cell lines. It was chosen to evaluate its mode of action in these cancer cell lines. The cell cycle study showed that the phosphonate derivative, compound 8, is the most active inhibitor of the cell cycle at the G0/G1 phase, inducing apoptosis independently of Caspase-3 and causing an increase in the mitochondrial membrane potential (ΔΨm) in the HT-1080 cell lines. Molecular docking studies of this phosphonate derivative into the MMP-2 and MMP-9 metalloproteinases receptors demonstrated the relevance of triazole scaffolds and the pendant phosphonate group in establishing -anion, -alkyl and hydrogen bonding type interactions with residual components in the active MMP pocket

Efficient ultraviolet-light energy dissipation by an aromatic ketone

Experimental evidence on the efficiency of 2,2'4,4'-tetramethoxybenzil for UV-light energy dissipation is provided. This non-phenolic aromatic ketone has a low energy triplet which quickly decays to the ketone ground state, thus avoiding the generation of undesirable reactive species.El Moncef, Abdelkarim, [email protected] ; Cuquerella Alabort, Maria Consuelo, [email protected] ; Zaballos Garcia, Elena, [email protected] ; Ramirez de Arellano Sanchez, Maria del Carmen, [email protected] ; Stiriba, Salah Eddine, [email protected] ; Perez Prieto, Julia, [email protected]

The potential use of activated carbon prepared from Ziziphus species for removing dyes from waste waters

Abstract In this study, the adsorption potential of activated carbon prepared from Ziziphus mauritiana nuts for the removal of methylene blue (MB) from aqueous solution has been investigated using batch mode experiments. The effects of some operating parameters on the removal dye such as, initial pH (2–12), temperature (298–328 K), initial MB concentration (20–100 mg L−1), and contact time (5–70 min) were investigated. Adsorption kinetic showed that the rate adsorption followed the pseudo-second-order kinetic model. Four adsorption isotherms models were applied to experimental equilibrium data (Langmuir, Freundlich, Redlich–Peterson, and Fritz–Schlunder) and the different constants were calculated using non-linear equations models. Fritz–Schlunder model was found the best one to describe the adsorption process which suggests that the adsorption of MB onto activated carbon derived from Ziziphus mauritiana is heterogeneous with a multilayer. Thermodynamic adsorption showed that the process was endothermic and spontaneous in nature