A new copper(II) Schiff base complex immobilized on silica-coated nanomagnetic Fe 3 O 4 was synthesized from acetylacetonate (acac) and 2aminothiophenol (ATP). The newly synthesized nanocatalyst, Fe 3 O 4 @SiO 2acac-2ATP-Cu(II), was structurally characterized using several analytical techniques. The catalytic activity of the Fe 3 O 4 @SiO 2 -acac-2ATP-Cu(II) nanoparticles was investigated for the synthesis of pyrano[2,3-b]pyridine derivatives from the one-pot three-component reaction of aldehydes, malononitrile and 3-cyano-6-hydroxy-4-methylpyridin-2(1H)-one. A high catalytic performance was exhibited by this nanocatalyst under solvent-free conditions and excellent yields of the products were achieved in reasonably short reaction times. The nanoparticles could be easily separated from the reaction mixture simply by magnetic decantation and reused for several consecutive runs without significant loss of catalytic activity. KEYWORDS acac-2ATP Schiff base-Cu(II) complex, Fe 3 O 4 -immobilized Schiff base copper complex, nanomagnetic Fe 3 O 4 , nanoparticle, pyranopyridine
Thiourea dioxide was immobilized on γ‐Fe2O3@Cu3Al‐LDH magnetic nanoparticles to prepare the γ‐Fe2O3@Cu3Al‐LDH‐TUD MNPs. The structure and properties of these magnetic nanoparticles were established by FT‐IR, EDX, SEM, XRD, and hystogram of particle size analytical methods. The results obtained from these analytical methods confirmed the successful immobilization of the thiourea dioxide onto the magnetic support. The synthesized magnetic nanoparticles (MNPs) exhibited high catalytic activity in one‐pot three‐component reactions under mild and solvent‐free conditions for the synthesis of diverse ranges of dihydropyrano[3,2‐c]pyrazoles and dihydropyrano[3,2‐c]chromens. All the reactions proceeded smoothly to furnish the respective products in excellent yields. Simple isolation of the products, avoidance of harmful organic solvents, versatility of the catalyst and its easy magnetic separation and reusability with no significant loss of activity are the main advantages of the present method.
An efficient synthetic method for the heterogenization of bifunctional zwitterionic HEPES catalyst on LDH modified γ-Fe 2 O 3 magnetic nanoparticles (MNPs) was developed to create a novel polar catalytic environment for tandem catalysis. The efficiency of the resulted acid/base bifunctional catalyst (γ-Fe 2 O 3 @Cu 3 Al-LDH/HEPES) was investigated in Biginelli-like synthesis of biologically active pyrazolo [3,4-d]pyrimidines via the cyclocondensation of 3-methyl, 1-phenyl-H1-pyrazole-5-ol with various aromatic aldehydes and urea derivatives in a mixture of water and ethanol (1:1) under reflux conditions. Besides, the desired products were reached with high conversions and powerful reusability. Utilization of simple and mild reaction conditions, hybrid bifunctional catalytic groups, short reaction time, green and safe solvent, high catalytic performance and good recyclability, easy purification of the products, and simple magnetically work-up make this methodology an interesting and effective option in the Biginelli reaction.
Herein, we described the synthesis of γ-Fe2O3@HAP-GndCl MNPs as an efficient and recyclable nanocatalyst for synthesis of new pyranopyridine derivatives under solvent-free condition and then evaluated for theirs antioxidant and antifungal activities.
A magnetically separable cobalt complex of macrocyclic pseudo-crown ether (PCE) immobilized on magnetic Cu/Al-layered double hydroxide (γ-Fe 2 O 3 @Cu 3 Al-layered double hydroxide (LDH)/PCE-Co) was readily fabricated using a simple four-step postsynthetic modification strategy. This newly prepared nanocomposite was characterized by different chemo-physical approaches, including Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectroscopy (ICP-OES), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), nitrogen adsorptiondesorption isotherms, energy-dispersive X-ray spectroscopy (EDX), and elemental mapping. The catalytic performance of these nanoparticles (NPs) was explored in the synthesis of diverse 1H-chromeno[2,3-b]pyridine-3-carbonitrile derivatives via one-pot three-component reactions under green reaction conditions. Environmentally benign reaction conditions, simple separation, high yields of the reactions, versatility, easy magnetic separation, and reusability for several runs without significant loss of catalytic performance are the key advantages that make this protocol an ideal alternative method for the synthesis of chromene derivatives.
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