Synthesis of a novel and reusable biological urea based acidic nanomagnetic catalyst: Application for the synthesis of 2‐amino‐3‐cyano pyridines via cooperative vinylogous anomeric based oxidation

Abstract

In the current study, a novel and reusable biological urea based nano magnetic catalyst namely Fe3O4@SiO2@(CH2)3‐urea‐benzimidazole sulfonic acid was designed and synthesized. The structure of the titled catalyst was fully characterized using several skills including Fourier transform infrared (FT‐IR) spectroscopy, energy dispersive X‐ray (EDX) analysis, X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermo gravimetric analysis/differential thermal analysis (TG/DTG) and vibrating sample magnetometer (VSM). Then, the catalytic performance of Fe3O4@SiO2@(CH2)3‐urea‐benzimidazole sulfonic acid was successfully inspected towards the multicomponent synthesis of 2‐amino‐3‐cyano pyridine derivatives through a vinylogous anomeric based oxidation pathway.

Novel pseudopolymeric magnetic nanoparticles as a hydrogen bond catalyst for the synthesis of tetrahydrodipyrazolopyridine derivatives under mild reaction conditions

“…The magnetic properties of novel pseudopolymeric magnetic nanoparticles were also studied by VSM analysis. The obtained data represent saturation at about 40 emu g −1 (decreased compared with the Fe 3 O 4 nanoparticles [37] ), which confirms the successful modifi-F I G U R E 7 VSM analysis of the prepared novel pseudopolymeric magnetic nanoparticles F I G U R E 6 TG/DTG plots of the prepared novel pseudopolymeric magnetic nanoparticles cation of the surface of Fe 3 O 4 nanoparticles and ensures easy separation of the catalyst from the reaction mixture by applying a simple external magnet (Figure 7).…”

“…Herein, in pursuit of our previous investigations for introducing reusable nanomagnetic catalysts [37][38][39] also, in the light of biological importance of tetrahydrodipyrazolopyridine derivatives and persuasive position of hydrogen-bonding in catalysis, we reported the design, synthesis, characterization, and catalytic performance of novel pseudopolymeric magnetic nanoparticles with urea linkers (as a heterogeneous catalyst with the hydrogen bond capability) towards the synthesis of tetrahydrodipyrazolopyridines (Schemes 1 and 2).…”

Magnetically recoverable catalysts for the preparation of pyridine derivatives: an overview

“…Fe 3 O 4 was then functionalized with tetraethyl orthosilicate (TEOS) in toluene under reux conditions to give Fe 3 O 4 @SiO 2 4, which was reacted with ligand 101 to yield Fe 3 -O 4 @SiO 2 @(CH 2 ) 3 -urea-benzimidazole 102, followed by the reaction with chlorosulfuric acid in dichloromethane to obtain Fe 3 O 4 @SiO 2 @(CH 2 ) 3 -urea-benzimidazole sulfonic acid 103 (Scheme 36). 64 Fe 3 O 4 @SiO 2 @(CH 2 ) 3 -urea-benzimidazole sulfonic acid 103 was employed in the synthesis of 2-amino-3-cyano pyridines 23 through the multicomponent reaction of benzaldehyde 9, malononitrile 16, methyl isopropyl ketone 31, and ammonium acetate 10 under solvent-free conditions at 70 C (Scheme 37). 64 Initially, according to previous works, 65 According to the results, the aldehydes with an electronwithdrawing group provided higher yields in comparison with electron-donating groups.…”

“…64 Fe 3 O 4 @SiO 2 @(CH 2 ) 3 -urea-benzimidazole sulfonic acid 103 was employed in the synthesis of 2-amino-3-cyano pyridines 23 through the multicomponent reaction of benzaldehyde 9, malononitrile 16, methyl isopropyl ketone 31, and ammonium acetate 10 under solvent-free conditions at 70 C (Scheme 37). 64 Initially, according to previous works, 65 According to the results, the aldehydes with an electronwithdrawing group provided higher yields in comparison with electron-donating groups. 70 Multi-walled carbon nanotubes systems MWCNTs-COOH 123 (ref.…”

A novel magnetically recyclable semi‐dendrimer catalyst‐based ethanolpyridole supported on ferrite nanoparticles (HNPs@Py) for the synthesis of biscoumarin and dihydropyrano[3,2‐c]chromene derivatives

“…Magnetic nanoparticles were easily separated from reaction by a magnet. [6][7][8][9] In addition, magnetic nanoparticles have many applications in industrial such as electronic devices, [10] information storage, [11] magnetic resonance imaging (MRI), [12] and drug-delivery technology. [13] Among various magnetic nanoparticles, iron oxide (Fe 3 O 4 ) has been studied extensively.…”