Silver, iron, and nickel immobilized on hydroxyapatite‐core‐shell γ‐Fe₂O₃ MNPs catalyzed one‐pot five‐component reactions for the synthesis of tetrahydropyridines by tandem condensation of amines, aldehydes, and methyl acetoacetate

Abstract

In this study, Ag, Ni2+, and Fe2+ immobilized on hydroxyapatite‐core‐shell γ‐Fe2O3 nanoparticles (γ‐Fe2O3@HAp‐Ag, γ‐Fe2O3@HAp‐Ni2+, and γ‐Fe2O3@HAp‐Fe2+) as a new and reusable Lewis acid magnetic nanocatalyst was successfully synthesized and reported for an atom economic, extremely facile, and environmentally benign procedure for the synthesis of highly functionalized tetrahydropyridines derivatives 4a‐t is described by one‐pot five‐component reaction of 2 equiv of aldehydes 1, 2 equiv of amines 2, and 1 equiv of methyl acetoacetate 3 in EtOH at room temperature in good to high yields and short reaction time. The presented methodology offers several advantages such as easy work‐up procedure, reusability of the magnetic nanocatalyst, operational simplicity, green synthesis avoiding toxic reagents and solvent, mild reaction conditions, and no tedious column chromatographic separation.

Applications of iron and nickel immobilized on hydroxyapatite‐core‐shell γ‐Fe2O3 as a nanomagnetic catalyst for the chemoselective oxidation of sulfides to sulfoxides under solvent‐free conditions

“…Recently, we focused on developing hydroxyapatite‐core‐shell γ‐Fe 2 O 3 systems for organic transformations. In the continuation of our study about developing hydroxyapatite‐core‐shell γ‐Fe 2 O 3 systems and other catalysts for organic transformations, here, we decided to use γ‐Fe 2 O 3 @HAp‐Ni 2+ and γ‐Fe 2 O 3 @HAp‐Fe 2+ as a new and reusable heterogeneous magnetic nanocatalyst for the selective oxidation of sulfides to sulfoxides with 33% aqueous H 2 O 2 (0.5 mL) as an oxidant at room temperature (Scheme ).…”

Fe3O4@APTES@isatin-SO3H as heterogeneous and efficient catalyst for the synthesis of quinoxaline derivatives

“…Recently, the chemists have greatly focused on developing the eco-friendly catalysts and methods in the synthetic organic material and industrial fields [1,2].Over the last few decades, a growing research interest has been directed towards the preparation and application of highly efficient and recyclable catalysts in the modern synthetic processes [3][4][5][6].Magnetic Fe 3 O 4 nanoparticles have emerged as privileged support for immobilization of various functional groups such as phosphorous, nitrogen and organic moieties owing to the presence of high density hydroxyl groups on their surface, high surface area, high stability, facile magnetic separation, environmental benignity and high loading capacity [7][8][9][10][11][12][13][14][15][16][17][18]. Among the heterocyclic compounds, quinoxaline and derivatives are the most important compounds due to their biological and pharmacological properties which perform antifungal [19], insecticide [20], antibacterial [21], anticancer, antimalarial, anti-HIV [22] and antibiotics [23] activities.…”

Zinc(II)‐poly(urea‐formaldehyde) supported on magnetic nanoparticles: A hybrid nanocatalyst for green synthesis of spiropyrans, spiroxanthenes, and spiropyrimidines

“…[ 10 ] In addition, they can be used as catalysts in chemical processes. [ 11–21 ] As a result, ferrite spheres with hollow structures have many practical applications in the fields of catalysis, adsorbents, and gas sensors and attract much attention from researchers. [ 6 ] Cobalt ferrite can be used as magnetic support due to its moderate saturation magnetization, low cost, high chemical stability, and mechanical strength.…”