Synthesis and characterization of copper(II) Schiff base complex supported on Fe₃O₄ magnetic nanoparticles: a recyclable catalyst for the one‐pot synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones

Abstract

Fe 3 O 4 -Schiff base of Cu(II) is found to be a recyclable and heterogeneous catalyst for the rapid and efficient synthesis of various 2,3-dihydroquinazolin-4(1H)-one derivatives from the two-component condensation of 2-aminobenzamide and an aldehyde. This reaction is simple, green and cost-effective. Separation and recycling can also be easily done by magnetic decantation of the Fe 3 O 4 nanoparticles with an external magnet. The prepared catalyst was characterized using thermogravimetry, Fourier transform infrared spectroscopy, vibrating sample magnetometry, inductively coupled plasma analysis, X-ray diffraction and scanning electron microscopy.

An Efficient Green Protocol for Synthesis of 2,3‐Dihydroquinazolin‐4(1H)‐ones Using SBA‐16/GPTMS‐TSC‐CuIunder Solvent‐Free Conditions

“…There are a variety of methods in the literature for the synthesis of 2,3‐dihydroquinazolin‐4(1 H )‐one derivatives with their own merits and demerits: (a) condensation of anthranilamide with an aldehyde or ketone; (b) desulfurization of 2‐thioxo‐4(3 H )‐ quinazolinones; (c) reaction of isatoic anhydride with Schiff bases; (d) one‐step conversion of 2‐nitrobenzamides to 2,3‐dihydro‐4(1 H )‐quinazolinones; (e) condensation of anthranilamide with benzyl; (f) two‐step synthesis starting from isatoic anhydride and amines, then was annulated with ketones; (g) a one‐pot three‐component condensation of isatoic anhydride, aldehydes and amines . Of these, condensation of anthranilamide with an aldehyde or ketone is one of the simplest and direct methods of 2,3‐dihydroquinazolin‐4(1 H )‐onse preparation using a variety of homogeneous or heterogeneous catalysts such as molecular iodine (I 2 ), cyanuric chloride, morpholinoethanesulfonic acid NH 4 Cl, tetrabutylammonium bromide (TBAB), p‐sulfonic acid calix arene, [Al(H 2 PO 4 ) 3 ], [bmim]HSO 4 , Sc(OTf) 3 , ZrCl 4 , Y(OTf) 3 , BiBr 3 , NaHSO 4 , lactic acid, heteropoly acids, β‐cyclodextrin‐SO 3 H, SiO 2 ‐PPA, [PYC 4 SO 3 H][HSO 4 ]/A300SiO 2 , Fe 3 O 4 nanoparticles, cellulose‐SO 3 H, β‐cyclodextrin, Cu(NO 3 ) 2 /F 3 O 4 ‐DETA, amberlyst‐15, Fe 3 O 4 ‐chiff base of Cu(II), Sc(OTf) 3 fluorous bis(oxazolines), chiral SPINOL‐phosphoric acids, 3 A°MS, SiO 2 ‐H 3 PW 12 O 40 , TBAHS or by electrochemical reactions . Although, the reported synthetic protocols produce good results in many instances, some of them associated with at least one of the following imperfections: harsh reaction conditions, prolonged‐time period, unsatisfactory yields, and use of environmentally harmful solvent, expensive moisture‐sensitive catalysts, hazardous acid catalysts, high catalyst loading, expensive reagent, and tedious workup conditions.…”

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“…Schiff bases also show some analytical applications [9]. Schiff bases are characterized by the -N=CH-(imine) group which imports in elucidating the mechanism of transamination and rasemination reaction in biological system [10,11]. Schiff bases have been studied for their important properties in catalysis [12].…”

Immobilization of nickel ions onto the magnetic nanocomposite based on cross‐linked melamine groups: Effective heterogeneous catalyst for N‐Arylation of Arylboronic acids

“…Among them, magnetic supported catalysts have attracted great attention in organic synthesis because of their simple separation by using an external magnet . However, the main problem here is the low loading of immobilized nickel complexes onto the magnetic nanoparticles . The activity of heterogeneous catalysts strongly depends on the loading amount of their immobilized homogenous part …”

“…[51,[55][56][57][58] However, the main problem here is the low loading of immobilized nickel complexes onto the magnetic nanoparticles. [59][60][61][62] The activity of heterogeneous catalysts strongly depends on the loading amount of their immobilized homogenous part. [63] An innovative way for increasing the loading amounts of nickel is immobilization of metal ions onto the crosslinked polymeric networks.…”