Immobilized Cu(II) Schiff base complex supported on Fe₃O₄ magnetic nanoparticles: A highly efficient and reusable new catalyst for the synthesis of pyranopyridine derivatives

Abstract

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

Fe3O4‐supported Schiff‐base copper (II) complex: A valuable heterogeneous nanocatalyst for one‐pot synthesis of new pyrano[2,3‐b]pyridine‐3‐carboxamide derivatives

“…On the basis of our previous report, [86] we proposed a plausible mechanism for Fe 3 O 4 @SPNC catalyzed Next, a Michael-type nucleophilic addition reaction occurs between the intermediate (I) and 3-cyano-6hydroxy-4-methyl-pyridin-2(1H)-one to afford the adduct (II). Finally, the intramolecular cyclization of (II) into the intermediate (III) is followed by tautomerization to furnish the respective product.…”

“…On the basis of our previous report, [86] we proposed a plausible mechanism for Fe 3 O 4 @SPNC catalyzed synthesis of pyrano[2,3-b]pyridine-3-carboxamides (Scheme 4). Initially, a Knoevenagel-type condensation reaction takes place between 3-iminoacrylamide (generated from the catalyst-activated isomerization of 2isocyanoacetamide) and the aldehyde in the presence of Fe 3 O 4 @SPNC as a Cu (II)-based Lewis acid nanocatalyst to provide the 3-aryl-2-cyanoacrylamide intermediate (I).…”

β‐Alanine‐functionalized magnetic graphene oxide quantum dots: an efficient and recyclable heterogeneous basic catalyst for the synthesis of 1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐dione and 2,3‐dihydroquinazolin‐4(1H)‐one derivatives

“…GO was prepared via the modified Hummers method. [ 62,63 ] According to this method, 1.25 g of natural graphite powder was stirred in 62 mL of H 2 SO 4 for 24 hr. Then, 7.5 g of KMnO 4 was slowly added into the mixture and stirred for 72 hr at 50 °C.…”

“…Following our ongoing efforts for the development of more benign and efficient heterogeneous nanocatalysts and their catalytic applications in organic transformation reactions, including the synthesis of heterocyclic compounds, [ 57–61 ] herein we report the novel synthesis of magnetic β‐alanine‐functionalized GO quantum dot (GOQD), Fe 3 O 4 @GOQD‐ N ‐(β‐alanine), nanoparticles as a novel catalyst. This magnetic Fe 3 O 4 @GOQD‐ N ‐(β‐alanine) nanoparticle was explored as an efficient, recyclable, and sustainable catalyst for one‐pot synthesis 1 H ‐pyrazolo[1,2‐ b ]phthalazine‐5,10‐diones ( 4a–i ) and 2,3‐dihydroquinazolin‐4(1 H )‐ones ( 7a–h ) (Scheme 1).…”

Copper and copper nanoparticles toxicity and their impact on basic functions in the body

“…The copper nanoparticles can be pure, but production of composites and mixed content structures provide better functional parameters. Advanced production techniques like thermal sintering (147), laser assisted sintering (148), electrodeposition (149), biotechnological processes (150), standard chemical synthesis (151,152) and click chemistry (151) and chemical properties. Antimicrobial applications (153,154) or other regulation of microorganism growth (155), use of unique optical properties like fl uorescence (156) including application to improving of quantum dots properties (157) and sensor systems, where the copper nanoparticles can carry another functional part like biomolecules (158) or serve as pseudoenzymes (159)(160)(161) are examples of specifi c use.…”