Knoevenagel Condensation of Aldehydes and Ketones with Malononitrile Catalyzed by Amine Compounds-Tethered Fe3O4@SiO2 Nanoparticles

Chitosan bead containing metal-organic framework encapsulated heteropolyacid as an efficient catalyst for cascade condensation reaction

Using cyclodextrin and chitosan that are bio-based compounds, a novel bi-functional catalytic composite is designed, in which metal-organic framework encapsulated phosphomolybdic acid was incorporated in a dual chitosan-cyclodextrin nanosponge bead. The composite was characterized via XRD, TGA, ICP, BET, NH₃-TPD, FTIR, FE-SEM/EDS, elemental mapping analysis and its catalytic activity was examined in alcohol oxidation and cascade alcohol oxidation-Knoevenagel condensation reaction. It was found that the designed catalyst that possess both acidic feature and redox potential could promote both reactions in aqueous media at 55 °C and various substrates with different electronic features could tolerate the aforementioned reactions to furnish the products in 75-95% yield. Furthermore, the catalyst could be readily recovered and recycled for five runs with slight loss of the catalytic activity. Notably, in this composite the synergism between the components led to high catalytic activity, which was superior to each component. In fact, the amino groups on the chitosan served as catalysts, while cyclodextrin nanosponge mainly acted as a phase transfer agent. Moreover, measurement of phosphomolybdic acid leaching showed that its incorporation in metal-organic framework and bead structure could suppress its leaching, which is considered a drawback for this compound. Other merits of this bi-functional catalyst were its simplicity, use of bio-based compounds and true catalysis, which was proved via hot filtration.

Synthesis of benzylidenemalononitrile by Knoevenagel condensation through monodisperse carbon nanotube-based NiCu nanohybrids

Monodisperse nickel/copper nanohybrids (NiCu@MWCNT) based on multi-walled carbon nanotubes (MWCNT) were prepared for the Knoevenagel condensation of aryl and aliphatic aldehydes. The synthesis of these nanohybrids was carried out by the ultrasonic hydroxide assisted reduction method. NiCu@MWCNT nanohybrids were characterized by analytical techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. According to characterization results, NiCu@MWCNT showed that these nanohybrids form highly uniform, crystalline, monodisperse, colloidally stable NiCu@MWCNT nanohybrids were successfully synthesized. Thereafter, a model reaction was carried out to obtain benzylidenemalononitrile derivatives using NiCu@MWCNT as a catalyst, and showed high catalytic performance under mild conditions over 10-180 min.

Magnetic core–shell dendritic mesoporous silica nanospheres anchored with diamine as an efficient and recyclable base catalyst

In the present study, diamine-functionalized magnetic core–shell dendritic mesoporous silica nanospheres have been successfully synthesized by an oil–water biphasic stratification-coating strategy.

Highly efficient FeNP-embedded hybrid bifunctional reduced graphene oxide for Knoevenagel condensation with active methylene compounds

Novel hybrid bifunctional FeNPs/PPD@rGO for Knoevenagel condensation reaction with 100% conversion and yield.

Arylboronic acids inhibit P2X7 receptor function and the acute inflammatory response

The P2X7 receptor (P2X7R) is an ion channel which is activated by interactions with the extracellular ATP molecules. The molecular complex P2X7R/ATP induces conformational changes in the protein subunits, opening a pore in the ion channel macromolecular structure. Currently, the P2X7R has been studied as a potential therapeutic target of anti-inflammatory drugs. Based on this, a series of eight boronic acids (NO) analogs were evaluated on the biologic effect of this pharmacophoric group on the human and murine P2X7R. The boronic acids derivatives NO-01 and NO-12 inhibited in vitro human and murine P2X7R function. These analogs compounds showed effect better than compound BBG and similar to inhibitor A740003 for inhibiting dye uptake, in vitro IL-1β release and ATP-induced paw edema in vivo. In both, in vitro and in vivo assays the compound NO-01 showed to be the hit compound in the present series of the arylboronic acids analogs. The molecular docking suggests that the NO derivatives bind into the upper body domain of the P2X7 pore and that the main intermolecular interaction with the two most active NO derivatives occur with the residues Phe 95, 103 and 293 by hydrophobic interactions and with Leu97, Gln98 and Ser101 by hydrogen bonds.. These results indicate that the boronic acid derivative NO-01 shows the lead compound characteristics to be used as a scaffold structure to the development of new P2X7R inhibitors with anti-inflammatory action.

Lanthanide–EDTA complexes covalently bonded on Fe3O4@SiO2 magnetic nanoparticles promote the green, stereoselective synthesis of N-acylhydrazones

Highly efficient stereoselective synthesis of E–N-acylhydrazones using magnetic nanoparticles-Ln³⁺ as heterogeneous catalysts.

Synthesis and Evaluation of the Anticancer and Trypanocidal Activities of Boronic Tyrphostins

Molecules containing an (cyanovinyl)arene moiety are known as tyrphostins because of their ability to inhibit proteins from the tyrosine kinase family, an interesting target for the development of anticancer and trypanocidal drugs. In the present work, (E)-(cyanovinyl)benzeneboronic acids were synthesized by Knoevenagel condensations without the use of any catalysts in water through a simple protocol that completely avoided the use of organic solvents in the synthesis and workup process. The in vitro anticancer and trypanocidal activities of the synthesized boronic acids were also evaluated, and it was discovered that the introduction of the boronic acid functionality improved the activity of the boronic tyrphostins. In silico target fishing with the use of a chemogenomic approach suggested that tyrosine-phosphorylation-regulated kinase 1a (DYRK1A) was a potential target for some of the designed compounds.