Synthesis of pyrazole derivatives in the presence of a dioxomolybdenum complex supported on silica-coated magnetite nanoparticles as an efficient and easily recyclable catalyst

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In this work, a copper Schiff base complex immobilized on silica‐coated Fe3O4 nanoparticles is synthesized, and studied as a highly efficient, recyclable, green and heterogeneous catalyst for the preparation of polysubstituted pyrroles under solvent‐free and mild conditions. This new catalyst was characterized by different techniques, such as Fourier transform infrared (FT‐IR), X‐ray powder diffraction (XRD), field‐emission scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), inductively coupled plasma (ICP) and vibrating sample magnetometry (VSM). The simple and environmentally one‐pot multicomponent condensation of nitromethane, an aryl aldehyde, a 1,3‐dicarbonyl compound and an amine in the presence of above catalyst affords the title compounds at room temperature. At the end, we compared the results for the synthesis of polysubstituted pyrroles in the presence of our nanocatalyst with previously reported catalysts in the literature.

Section: Resultssupporting

confidence: 92%

Section: Resultssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

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Copper Schiff base complex immobilized on silica‐coated Fe₃O₄ nanoparticles: a recoverable and efficient catalyst for synthesis of polysubstituted pyrroles

Hamrahian

Rakhtshah

Davijani

et al. 2018

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“…The emphasis was on organocatalysts immobilization on Fe 3 O 4 coated with SiO 2 and the need for functional active reagents, for example CPTMS (3‐chloroopropyltrimethoxysilane) or APTES (3‐aminopropyltriethoxysilane) . To save their cost and to reduce the synthetic steps for preparation of supported organocatalysts on Fe 3 O 4 ‐SiO 2 , significant functional groups in the backbone of the coordinated ligands to the central metal ion of the catalyst could interact with Fe 3 O 4 ‐SiO 2 nanoparticles to be immobilized on it, for example ―OH and ―OR groups …”

Section: Introductionmentioning

confidence: 99%

Catalytic evaluation of copper (II) N‐salicylidene‐amino acid Schiff base in the various catalytic processes

Al-Hussein

Adam

2020

N‐Salicylidene amino acid Schiff base sodium sulfonate salt, as a tridentate dibasic chelating ligand, was obtained from the common condensation of salicylaldehyde‐5‐sodium sulfonate with tyrosine (HPST). The internal formed ligand coordinated to Cu2+ ion in an aqueous media affording new Cu (II)‐complex (Cu‐PST), which characterized by various physico‐chemicals spectral tools. The mononuclear complex was evaluated as a homogeneous and heterogeneous catalyst in the (ep)oxidation protocols of 1,2‐cyclooctene and benzyl alcohol. Heterogeneously, Cu‐PST was immobilized on Fe3O4‐SiO2, as nanoparticles. The heterogeneous catalyst was characterized by infrared, X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, energy‐dispersive spectroscopy, Brunauer−Emmett−Teller and magnetism. Homogeneously, the temperature, solvent and oxidant influences were examined in the catalytic reactions to realize the best reaction conditions. Cu‐catalyst exhibited better catalytic performance in the (ep)oxidation processes homogeneously than that in the heterogeneous phase at 80°C for 2 hr in acetonitrile. Reusability of the homogeneous catalyst was for a maximum of three times in the (ep)oxidation reaction, whereas the heterogeneous catalyst was active for six times. A mechanistic pathway was proposed for both catalysts, comparatively.

“…A literature search reveals that we and others have explored different usages of magnetic Fe 3 O 4 nanoparticles as magnetically recoverable catalysts in organic reaction processes. Additionally, transition metal Schiff‐base complexes have attracted much interest in the field of catalysis because of the extensive variety of applicability, like chemical stability, controlling the performance of metals in a large diversity of valuable catalytic transformations and stabilization of different metals in various oxidation states .…”

Section: Introductionmentioning

confidence: 99%

Preparation, characterization and catalytic application of molybdenum Schiff‐base complex immobilized on silica‐coated Fe₃O₄ as a reusable catalyst for the synthesis of pyranopyrazole derivatives

Hamrahian

Salehzadeh

Rakhtshah

et al. 2018

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A recoverable molybdenum Schiff‐base complex immobilized on silica‐coated Fe3O4 nanoparticles was prepared and characterized. This superparamagntic nanocatalyst, which is separable using an external magnet, can be used as an efficient catalyst for the promotion of the synthesis of pyranopyrazole derivatives. A variety of desired products were obtained in high to excellent yields within short times. In comparison with other catalysts employed in the condensation of various aromatic aldehydes, malononitrile and 3‐methyl‐1‐phenyl‐2‐ pyrazoline‐5‐one, the present catalyst showed a much higher activity in terms of mild conditions and short reaction time. The catalyst can be reused for several times without significant loss of activity.