Copper(II) Complex Supported on Fe₃O₄@SiO₂ Coated by Polyvinyl Alcohol as Reusable Nanocatalyst in N‐Arylation of Amines and N(H)‐ Heterocycles and Green Synthesis of 1H‐Tetrazoles

Abstract

In this paper, copper(II) based catalyst bearing polyvinyl alcohol immobilized on Fe3O4@SiO2 was synthesized and fully characterized by FT‐IR, XRD, TEM, FE‐SEM, DLS, UV‐Vis, XPS, EDX, TGA, VSM, NMR, ICP and elemental analysis techniques. Then, the performance of this magnetic heterogeneous system was investigated in the N‐arylation of nitrogen heterocycles and alkyl amines with aryl halides to produce the desired coupled products in good to excellent yields without using external ligands or additives as promoters. Also, this reusable copper based magnetic nanocatalyst was employed in one‐pot three component and green synthesis of 5‐substituted 1H‐tetrazoles in excellent yields through the click reaction of aliphatic and aromatic aldehydes with hydroxylamine hydrochloride and azide salt. This catalytic system was easily recovered by a magnetic field and reused for at least 7 times without distinct deterioration in catalytic activity. Also, the analysis of the reaction mixture by the ICP technique showed that the leaching of the catalyst was negligible.

Anchoring of Cu (II)‐Schiff base complex on magnetic mesoporous silica nanoparticles: catalytic efficacy in one‐pot synthesis of 5‐substituted‐1H‐tetrazoles, antibacterial activity evaluation and immobilization of α‐amylase

“…Catalytic activity of Fe 3 O 4 @MCM-41-SB-Cu is compared with some other catalyst systems reported in the literature for the production of 5-phenyl 1H-tetrazole (Table 4). [33,[66][67][68][69][70][71][72][73][74] The results show that the mentioned magnetic nanocatalyst provides higher yield of the product in shorter reaction time. Furthermore, the catalyst is easily removed from the reaction mixture using an external magnetic field.…”

Functionalization of superparamagnetic Fe3O4@SiO2nanoparticles with a Cu(II) binuclear Schiff base complex as an efficient and reusable nanomagnetic catalyst forN‐arylation of α‐amino acids and nitrogen‐containing heterocycles with aryl halides

“…Moreover, the yield of the products was comparable to the previously reported homogeneous systems. [23,[56][57][58][59][60][61] 2 | EXPERIMENTAL…”

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

“…Hamad et al Esmaeilpour et al reported the catalytic use of Fe 3 O 4 @SiO 2 -TCT-PVA-Cu(II) for the N-arylation of N-containing heterocycles such as imidazoles (81a), indoles (81j), pyrrole (106a), piperazine (108e) and N-phenyl piperazines (109d) using aryl halides (82p) as the aryl coupling partner and sodium tert-butoxide as the base in DMF at 100 C in 86-96% yield (Scheme 255). 459 The same protocol was also extended for the synthesis of 5-phenyl 1H-tetrazoles (87c) by the reaction among substituted benzaldehyde (2), sodium azide (66) and hydroxylamine hydrochloride (275) in water under reux via click reaction (Scheme 256). The NPs were prepared by coating Fe 3 O 4 NPs with silica followed by their treatment with (3-chloropropyl)trimethoxysilane and 3-(3-hydroxy-propylamino)-propan-1-ol to obtain NPs having free hydroxyl groups.…”