Fe3O4@nano‐almondshell@OSi(CH2)3/2‐(1‐piperazinyl)ethylamine/Zn(II) abbreviated (FNAOSiPPEA/Zn(II)) as a Lewis acid/ Bronsted base double‐layer magnetic nano‐catalyst was prepared by immobilization of Zn‐diamine complex on functionalized nano‐almondshell coated Fe3O4 NPs. The properties of the FNAOSiPPEA/Zn(II) nano‐catalyst were identified by the of FT‐IR, FESEM, TGA, EDS‐MAP, XRD, VSM, and BET techniques. The catalytic performance of FNAOSiPPEA/Zn(II) as a strong and effective Lewis acid for the synthesis of 2‐aryl(alkyl)‐2,3‐dihydro‐1H‐naphtho[1,2‐e][1,3]oxazine derivatives, abbreviated ADNO, was evaluated. A three‐component reaction between formaldehyde, primary amines, and phenolic compounds such as β‐naphthol, α‐naphthol, phenol, and hydroquinone was occurred in this protocol. FNAOSiPPEA/Zn(II) can be reused four times with a slight loss of catalytic activity.
Background
Ball mill is an effective, and green method for the synthesis of heterocyclic compounds in very good yields. This method is a simple, economical, and environmentally friendly process. In this work, an efficient approach for the synthesis of pyranopyrazoles (PPzs) using ball milling and metal-free nano-catalyst (Nano-silica/aminoethylpiperazine), under solvent-free conditions was reported.
Results
The new nano-catalyst silica/aminoethylpiperazine was prepared by immobilization of 1-(2-aminoethyl)piperazine on nano-silica chloride. The structure of the prepared nano-catalyst was identified by FT-IR, FESEM, TGA, EDX, EDS-map, XRD, and pH techniques. This novel nano-catalyst was used for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives under ball milling and solvent-free conditions.
Conclusions
Unlike other pyranopyrazoles synthesis reactions, this method has advantages including short reaction time (5–20 min), room temperature, and relatively high efficiency, which makes this protocol very attractive for the synthesis of pyranopyrazoles derivatives.
The preparation and design of nano-catalysts based on magnetic biopolymers as green and biocompatible nano-catalysts have made many advances. This paper deals with the preparation of magnetite biopolymer-based Brønsted base nano-catalyst from a nano-almond (Prunus dulcis) shell. This magnetite biopolymer-based nano-catalyst was obtained through a simple process based on the core-shelling of nano-almond shell and Fe3O4 NPs and then the immobilization of 3-chloropropyltrimethoxysilane as linker and 2-aminoethylpiperazine as a basic section. Structural and morphological analysis of this magnetite biopolymer-based nano-catalyst were done using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, Thermogravimetric analysis, Vibrating sample magnetization, Energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller, and Transmission electron microscopy techniques. The performance of the synthesized Fe3O4@nano-almondshell/Si(CH2)3/2-(1-piperazinyl)ethylamine as a novel magnetite biopolymer-based nano-catalyst for the synthesis of dihydropyrano[3,2-c]chromene and tetrahydrobenzo[b]pyran was investigated and showed excellent efficiency.
Background
The magnetic nano-catalysts improve the contact between substrates and catalyst considerably and simple isolation of catalyst from reaction mixture. In this study, Fe3O4@nano-almondshell@OSi(CH2)3/2-(1-piperazinyl)ethylamine/Cu(II) abbreviated (FNAOSiPPEA/Cu(II)), was prepared, characterized and applied for the synthesis of 4H-pyrimido[2,1-b]benzothiazole.
Results
FNAOSiPPEA/Cu(II) as a bio-based nano-catalyst was prepared from the complexation of copper on 2-(1-piperazinyl)ethylamine, which was immobilized on Fe3O4@nano-almondshell@OSi(CH2)3 section. This new heterogeneous bifunctional Lewis acid/Bronsted base catalyst (FNAOSiPPEA/Cu(II)) was characterized by various techniques such as FT-IR, FESEM, TGA, EDS-MAP, XRD, VSM, BET, TEM, and XPS. So, the catalytic performance of this recyclable nano-catalyst was determined to promote the synthesis of 4H-pyrimido[2,1-b]benzothiazole derivatives at 100 °C under solvent-free conditions.
Conclusions
Magnetite nano-catalyst of (FNAOSiPPEA/Cu(II)) is easily separated by an external magnet and successfully reused up at least 3 times with a slight loss of yield of the desired product.
This paper deals with the preparation of magnetite biopolymer-based Brønsted base nano-catalyst from nano-almond (Prunus dulcis) shell. This magnetite biopolymer-based nano-catalyst was obtained through a simple process based on the core-shelling of nano-almond shell and Fe3O4 NPs and then the immobilization of 3-chloropropyltrimethoxysilane as linker and 2-aminoethylpiperazine as a basic section. Structural and morphological analyzes of this magnetite biopolymer-based nano-catalyst were done. The performance of the synthesized Fe3O4@nano-almondshell@OSi(CH2)3/2-(1-piperazinyl)ethylamine as a novel magnetite biopolymer-based nano-catalyst for the synthesis of dihydropyrano[3,2-c]chromene and tetrahydrobenzo[b]pyran was investigated and showed excellent efficiency.
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