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

Abstract

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.

Preparation and application of FNAOSiPPEA/Cu(II) as a novel magnetite almondshell based Lewis acid-Bronsted base nano-catalyst for the synthesis of pyrimidobenzothiazoles

“…And the second in 180–370 ℃ is ascribed to the decomposition of almondshell. The exothermic process observed in the temperature range of 385–400 ℃, which leads to the third stage of weight loss, can be related to the Fe 3 O 4 NPs decomposition [ 31 ]. The desired catalyst can be used in reactions around or below 200 ℃.…”

FNAOSiPPEA[]/Zn(II) as a Bifunctional Lewis Acid/ Bronsted Base Heterogeneous Magnetic Nanocatalyst Based on Nano‐Almond Shell for Synthesis of Naphtho[1,3]oxazine Derivatives**

“…The second weight loss in 180-370 °C, which is probably due to the decomposition of the nano-almond shell, and the third weight loss in the range of 370-400 °C, which could be related to the degradation of Fe 3 O 4 NPs. [32] These results indicate that the catalyst can be used in reactions around or below 200 °C. We have also studied magnetization behavior of FNAOSiPPEA/ Zn(II) by vibrating sample magnetization (VSM).…”

A decennary update on applications of metal nanoparticles (MNPs) in the synthesis of nitrogen- and oxygen-containing heterocyclic scaffolds

“…Salehzadeh et al reported the catalytic use of a molybdenum Schiff-base complex supported on Fe 3 O 4 @SiO 2 NPs for the synthesis of pyranopyrazoles using different approaches mediated by benzaldehyde, malononitrile, and 3methyl-1-phenyl-2-pyrazolin-5-one under solvent-free conditions at rt. 222 Recently, they also reported pyridinium tribromide ionic liquid-supported silica coated ferrite NPs for the efficient synthesis of 4-phenyl pyrimidines from triethoxy methane, ammonium acetate and substituted acetophenones. 223 Yavari et al reported the synthesis of 2-aryl imidazoles (83g)/ benzothiazoles (204a)/benzimidazoles (83h)/spermidine (206) derivatives via cyclocondensation with aromatic aldehydes catalyzed by functionalized magnetic core NPs (Fe 3 O 4 /SiO 2 / (CH 2 ) 3 N + Me 3 Br 3 ) under solvent-free conditions at 80 C in 89-95% yield (Scheme 108).…”