Current Catalysis - Volume 13, Issue 2, 2024

The gold-catalyzed benzannulation reaction of oxo-alkynes with alkenes or alkynes is one of the important and unique reactions in gold-catalyzed organic transformations.

In this manuscript, many facets of this reaction have been discussed concerning reactivity and selectivity, along with a new self-benzannulation process. The scope of this chemistry was extended to construct a phenanthrene moiety.

In addition, a palladium-gold dual catalytic arylation of isobenzopyrylium salts using arene-diazonium salts as an aryl group source and a one-pot isoquinoline synthesis is reported for the first time.

Moreover, a conductance measurement experiment was performed, which supports the formation of ionic species, most likely the isobenzopyrylium auric ate complex as an intermediate formed during the reaction process.

For catalyzing carbon-carbon and carbon-heteroatom bond formation reactions, core-shell nanocomposites have attracted particular attention as invincible heterogeneous catalysts. Heterocyclic motifs like pyrazole have been used in anticancer drugs. Moreover, DNA repair enzymes are also an efficient target for developing potential anticancer therapies.

Novel core-shell nanocomposite coal fly ash @CuO has been produced by loading the precursor Cu(NO3)2.3H2O on a thermally and chemically activated Coal Fly Ash (CFA) core. Triton X-100 surfactant was used to increase the uniform adhesive coating of the CuO shell on the fly ash core. The structure and physicochemical properties of the composite were elucidated through techniques, such as Fourier-Transform Infrared Spectroscopy (FT-IR), X-ray powder diffraction (XRD), Field Emission Scanning Electron Microscopy-Energy-Dispersive X-ray spectroscopy (FE-SEM and EDAX), Transmission Electron Microscopy, Selected Area Electron Diffraction (TEM and SEAD), and Brunauer-Emmett-Teller (BET) surface analysis. Then, the catalytic efficiency of CFA@CuO was checked for the synthesis of bis-pyrazole derivatives. Furthermore, we also executed docking simulations between 1QZQ and bis pyrazole molecules to assess the affinity and binding orientation of the ligand.

Compared to synthesized CuO nanoparticles, the catalytic activity of CFA@CuO could be found promising as it offers high yield and purity of bis-pyrazole derivatives. After the completion of the reaction, the catalyst was separated and recycled. It was found that the yield of this catalyst remained unchanged even after four consecutive runs. A docking simulation was performed between 1QZQ and bis-pyrazole derivatives, proving that pyrazoles are a better source for inhibiting selectively tyrosyl DNA phosphodiesterase I.

Herein, we report a convenient and efficient practical protocol for the preparation of 4, 4-(arylmethylene)-bis (3-methyl-1-phenylpyrazol-5-ols) and its derivatives using Tandem- Knoevenagel-Michael cyclocondensation of aromatic aldehydes, ethyl acetoacetate, and phenyl hydrazine using CFA@CuO nanocomposite as a heterogeneous nanoscale and recyclable catalyst. A molecular docking study concluded that 4’-(4-nitrophenylmethylene) bis(3-methyl-1phenyl-1H-pyrazol-5-ols) is a better inhibitor of lead against 1QZQ among all synthesized derivatives, suggesting it a potent hydrophobic lead drug candidate as phosphodiesterase inhibitor.

The present study aims to discuss the synthesis of various spiro-pyrano-oxoindole derivatives through a reaction involving isatin, malononitrile, and a CH-acid source in the presence of vitamin B12.

Eco-friendly solvents were utilized to synthesize the spiro-pyrano-oxoindole, resulting in high yields of all synthesized heterocyclic systems. Isatin and malononitrile were reacted with β-dicarbonyls as CH-acids in the presence of vitamin B12.

The results indicate that vitamin B12 is highly effective in generating spiro-pyrano-oxoindole derivatives. All synthesized compounds closely match previously reported compounds.

In conclusion, a new and effective method for synthesizing spiro-pyrano-oxoindole has been demonstrated using vitamin B12 as a biocatalyst.

A binuclear azomethine quinoxaline Schiff base copper (II) complex, [Cu2LCl2], having square-planar environment around each copper (II), has been synthesized.

The coordination of the azomethine quinoxaline Schiff base with copper (II) and its structure was studied by various physicochemical and spectroscopic measurements.

Catalytic activity of this complex in phenol hydroxylation reaction has been examined using H2O2 as a green oxidant.

Catalytic reaction conditions were optimized and under these conditions, 18.32 % conversion of phenol has been obtained for this catalyst

A four-coordinate ruthenium(II) quinoxaline Schiff base complex with formula [Ru2LCl2].H2O has been synthesized and characterized. The hydrogenation of benzene and toluene using this complex as a catalyst was studied in a semi-batch reactor.

At 60℃ with 2.82 × 10^-6 mol catalyst and 30 bar hydrogen pressure, turnover frequencies 7362 h^-1 and 5873 h^-1 have been found for the reduction of benzene (0.34 mol) and toluene (0.28 mol), respectively.

Both partial and complete reduction occurs with more selectivity for the formation of completely reduced products. The initial rate approach was used to study the kinetics of benzene hydrogenation, and the reaction was discovered to be first order with regard to benzene and the catalyst, while following Michaelis-Menton kinetics with respect to dihydrogen.

This kinetic data proposed an intermediate hydride/dihydrogen complex as the catalytically active species which controls the overall hydrogenation rate.