A Novel, Efficient, and Recoverable Basic Fe3O4@C Nano-Catalyst for Green Synthesis of 4H-Chromenes in Water via One-Pot Three Component Reactions

Nanomagnetic CoFe2O4@SiO2-EA-H3PO4 as a zwitterionic catalyst for the synthesis of bioactive pyrazolopyranopyrimidines and dihydropyrano[2,3-c]pyrazoles

This study presents the development of a phosphoric acid-based zwitterionic catalyst immobilized on CoFe2O4 nanoparticles [CoFe2O4@SiO2-EA-H3PO4]. The structure of the nanocatalyst CoFe2O4@SiO2-EA-H3PO4 was identified by applying several spectroscopic techniques, i.e. FT-IR, SEM, TEM, XRD, EDX, elemental Mapping, VSM, TGA, and BET techniques. The catalytic efficiency of CoFe2O4@SiO2-EA-H3PO4 was evaluated in the water-based multicomponent synthesis of pyrazolopyranopyrimidine and dihydropyrano[2,3-c]pyrazole derivatives. Subsequently, an exploration of the antibacterial properties of the compounds was conducted. The catalytic system offers several advantages, encompassing high efficiency, brief reaction duration, uncomplicated operation, and facile recycling of the catalyst.

Six-component synthesis and biological activity of novel spiropyridoindolepyrrolidine derivatives: A combined experimental and theoretical investigation

Petasites hybridus rhizome water extract was used as green media for the preparation of Ag/Fe₃O₄/CdO@multi-walled carbon nanotubes magnetic nanocomposites (Ag/Fe₃O₄/CdO@MWCNTs MNCs), and its activity was evaluated by using in the one-pot multicomponent reaction of isatins, acetyl chloride, secondary amines, vinilidene Meldrum’s acid, primary amines, and malononitrile in an aqueous medium at room temperature for the generation of spiropyridoindolepyrrolidine as new derivatives with tremendous output. In addition, organic pollutant reduction of 4-nitrophenol (4-NP) was carried out by generated Ag/Fe₃O₄/CdO@MWCNTs in water at room temperature. The results displayed that Ag/Fe₃O₄/CdO@MWCNTs were reduced as pollutants of organic compounds in a short time. The synthesized spiropyridoindolepyrrolidine has an NH₂ functional group that has acidic hydrogen and shows high antioxidant ability. Also, the spiropyridoindolepyrrolidine exhibited antimicrobial ability, and the method that is used for this purpose is the disk diffusion method, and two kinds of bacteria, Gram-positive and Gram-negative, were employed for this analysis. Also, to better understand the reaction mechanism density, functional theory-based quantum chemical methods have been applied. For the generation of spiropyridoindolepyrrolidine, the used process has many properties such as reactions with short time, product with good yields, and simple extraction of catalyst from the mixture of reaction.

Recent advances in the application of magnetic bio-polymers as catalysts in multicomponent reactions

Magnetic nanoparticles have attracted significant attention due to their high surface area and superparamagnetic properties. Bio-polymers composed of polysaccharides including alginate, cellulose, glucose, dextrin, chitosan, and starch can be immobilized on magnetic nanoparticles. Bio-polymers can be obtained from natural sources, such as plants, tunicates, algae, and bacteria. Bio-polymers obtained from natural sources have attracted attention due to their various properties including efficient functional groups, non-toxicity, low cost, availability, and biocompatibility. According to the targets of "green chemistry", the application of bio-polymers is effective in reducing pollution. Furthermore, they are excellent agents for the functionalization of magnetic nanoparticles to yield nanomagnetic bio-polymers, which can be applied as recoverable and eco-friendly catalysts in multicomponent reactions.

Green synthesis and investigation of antioxidant and antimicrobial activity of new schiff base of pyrimidoazepine derivatives: application of Fe3O4/CuO/ZnO@MWCNT MNCs as an efficient organometallic nanocatalyst

In this study, we synthesized schiff base of pyrimidoazepine derivatives in high yields using multicomponent reactions of isatins, alkyl bromides, activated acetylenic compounds, guanidine and aldehydes in the presence of Fe₃O₄/CuO/ZnO@ Multi Walled Carbon Nanotubes (MWCNT) as a high performance catalyst in water at room temperature. The Fe₃O₄/CuO/ZnO@MWCNT synthesizes using Petasites hybridus rhizome water extract as a green media and moderate base. As well Fe₃O₄/CuO/ZnO@MWCNT magnetic nanocomposites show a good improvement in the yield of the product and displayed significant reusable activity. Investigation of antioxidant ability of synthesized compounds using radical trapping of diphenyl-picrylhydrazine and ferric reduction power experiment is another purpose in this research. Also, the antimicrobial activity of some synthesized compounds proved by employing the disk diffusion test on Gram-positive and Gram-negative bacteria. This procedure has some benefits such as short reaction time, product with excellent yields, simple catalyst and products separation.

Green novel multicomponent synthesis and biological evaluation of new oxazolopyrazoloazepines and reduction of nitrophenols in the presence of Ag/Fe3O4/ZnO@MWCNT MNCs

In this research, new derivatives of oxazolopyrazoloazepines were synthesized in high yields using multicomponent reaction of anilines, oxalylchloride, alkyl bromides, activated acetylenic compounds, hydrazine and ethyl bromopyruvate in the presence of Ag/Fe₃O₄/ZnO@MWCNT magnetic nanocomposite (MNCs) as a high-performance magnetic catalyst in ionic liquid at room temperature. The Ag/Fe₃O₄/ZnO@MWCNT magnetic nanocomposites (MNCs) were synthesized using 1-octhyl-3-methyl imidazolium bromide ([OMIM]Br) as a stabilizer and soft template. Also, the catalytic activity of the Ag/Fe₃O₄/ZnO@MWCNT MNCs was evaluated in reduction of organic pollutants such as 4-nitrophenol (4-NP) in water at mild conditions. The results indicated that the biosynthesized nanocomposites (NCs) have high catalytic activity for organic pollutants within few seconds. Because of having benzazepine nucleus in the synthesized compounds, we investigate antioxidant property of some synthesized oxazolopyrazoloazepines by diphenyl-picrylhydrazine radical trapping and power of ferric reduction experiment. Short time of reaction, high yields of product, easy separation of catalyst and products are some advantages of this procedure.

PANI-Fe3O4@ZnO nanocomposite as magnetically recoverable organometallic nanocatalyst promoted synthesis of new Azo chromene dyes and evaluation of their antioxidant and antimicrobial activities

A new series of azo chromene dyes were synthesized via a facile cyclocondensation reaction of (E)-1,2-diphenyl-1-diazene and 4-aminocoumarin with 1:2 molar ratio catalyzed by the polyaniline-Fe₃O₄@ZnO nanocomposite (PANI-Fe₃O₄@ZnO). The salient features of this protocol lie in simple experimental procedure, moderate reaction conditions, and uses PANI-Fe₃O₄@ZnO nanocomposite as a magnetically separable heterogeneous catalyst. Two well-known methods were employed for assessing the antioxidant abilities of the target compounds, including free radical trapping of 2,2-diphenyl-1-picrylhydrazyl (DPPH), as well as ferric reducing antioxidant power assay. Also, several synthesized compounds were screened for their in vitro antimicrobial activities by employing the disk diffusion test on Gram-negative as well as Gram-positive bacteria.

Fe3O4@C@OSO3H as an efficient, recyclable magnetic nanocatalyst in Pechmann condensation: green synthesis, characterization, and theoretical study

Novel sulfonated carbon-coated magnetic nanoparticles (SCCMNPs; Fe₃O₄@C@OSO₃H) were designed, synthesized, characterized, and applied as an efficient nanocatalyst for green synthesis of coumarin derivatives through Pechmann condensation. The Fe₃O₄@C@OSO₃H was manufactured through a simple and inexpensive two-step procedure and characterized by FTIR, EDX, XRD, SEM, TEM, DLS, VSM, and TGA techniques. It was identified as an efficient heterogeneous catalyst in the Pechmann condensation of phenol derivatives and β-ketoesters, leading to high-yield coumarin derivatives under solvent-free conditions. The Fe₃O₄@C@OSO₃H removed after reaction finishing point by an external magnet, and it was reused fifteen times at the same conditions. Besides, theoretical studies were carried out using B3LYP/6-311++G(d,p) to more consideration of the reaction mechanism. The study of the frontier molecular orbitals, NBO atomic charges, molecular electrostatic potential of reactants, as well as Pechmann condensation mechanism was known very useful in suitable reactant choice. The reaction was performed through the electrophilic attack, dehydration, and trans-esterification, respectively.