A magnetic nanoparticle-supported sulfuric acid as a highly efficient and reusable catalyst for rapid synthesis of amidoalkyl naphthols

Magnetite-supported montmorillonite (K10) (nanocat-Fe-Si-K10): an efficient green catalyst for multicomponent synthesis of amidoalkyl naphthol

Montmorillonite (K₁₀) loaded on magnetite silica-coated nanoparticles was made using simple co-precipitation methods. The prepared nanocat-Fe-Si-K₁₀ was analyzed using some techniques including field emission-scanning electron microscopy (FE-SEM), inductive coupling plasma-optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), Fourier transmission-infrared spectra (FT-IR), energy dispersive X-ray spectroscopy (EDS), and wavelength-dispersive spectroscopy (WDX). The catalytic activity of the synthesized nanocat-Fe-Si-K₁₀ has been examined in one-pot multicomponent transformations for the synthesis of 1-amidoalkyl 2-naphthol derivatives under solvent-free conditions. Nanocat-Fe-Si-K₁₀ was determined to be very active, having the ability to be reused 15 times without significant loss of catalytic activity. The suggested technique has several advantages, including excellent yield, minimum reaction time, a straightforward workup, and catalyst recycling, all of which are essential green synthetic aspects.

New magnetic nanocomposite Fe3O4@Saponin/Cu(II) as an effective recyclable catalyst for the synthesis of aminoalkylnaphthols via Betti reaction

In this research, a new magnetic nanocomposite Fe₃O₄@Saponin/Cu(II) based on quillaja saponin was prepared and the catalyst structure was characterized thoroughly using FT-IR, EDS, TGA, XRD, VSM, HR-TEM, SEM, ICP, BET analyzes. The catalyst prepared in the three-component synthesis of several Betti bases, 1-(α-aminoalkyl)naphthols, under environmentally friendly conditions was used. The advantage of this reaction is the high efficiency of the products and the short reaction time. Furthermore, Fe₃O₄@Saponin/Cu(II) nano-catalyst is recoverable magnetically and is reusable for other processes with no reduction in its activity.

Synthesis of calixresorcarenes using magnetic poly triazine-benzene sulfonamide-SO3H

The purpose of this work is to develop a magnetically recyclable immobilized base catalyst for the green synthesis of calixresorcarenes. To achieve this, poly triazine-benzene sulfonamide (PTBSA) has been coated on magnetic Fe₃O₄ nanoparticles and subsequently chlorosulfonic acid has been supported to obtain Fe₃O₄@PTBSA-SO₃H. The structure of nano-Fe₃O₄@PTBSA-SO₃H was characterized by TEM, XRD, FT-IR, VSM, WDX, EDX, TGA/DSC and FE-SEM. The catalytic efficiency of this catalyst was also investigated in the synthesis of novel calixresorcarene derivatives. The advantages of heterogeneous nature, catalytic activity and the recyclability of the polymer support were also strengthened by advanced surface treatment. These key factors (basic sites, acidic sites and heterogeneity) play essential roles in the catalyst performance. This procedure has some advantages such as short reaction time, clean and fast work-up and easy separation of the catalyst by an external magnet.

Magnetic poly triazine-benzene sulfonamide-SO₃H was investigated for the synthesis of calixresorcarenes.

Copper(II) Anchored on Amine-Functionalized MMT: A Highly Efficient Catalytic System for the One-Pot Synthesis of Bispyrano[2,3-c]pyrazole Derivatives

In this study, preparation of pyridine-2-carboimine copper complex immobilized on amine-functionalized nanoclay montmorillonite K10 was reported. The products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and thermogravimetric analysis (TGA). The catalytic activity of this new nanocatalyst, as a natural, renewable, inexpensive, and heterogeneous catalyst, was very effective for the four-component condensation reaction of hydrazine hydrate (or phenyl hydrazine), malononitrile, β-ketoester, and terephthalaldehyde (or isophthalaldehyde) toward the synthesis of multisubstituted bispyrano[2,3-c]pyrazole derivatives. From the viewpoint of green chemistry, the advantages of this approach are accessibility, simplicity, and high yields synthesis. The catalyst was recycled and reused four times without significant loss of activity.

The anchoring of a Cu(ii)-salophen complex on magnetic mesoporous cellulose nanofibers: green synthesis and an investigation of its catalytic role in tetrazole reactions through a facile one-pot route

Today, most synthetic methods are aimed at carrying out reactions under more efficient conditions and the realization of the twelve principles of green chemistry. Due to the importance and widespread applications of tetrazoles in various industries, especially in the field of pharmaceutical chemistry, and the expansion of the use of nanocatalysts in the preparation of valuable chemical reaction products, we decided to use an (Fe3O4@NFC@NSalophCu)CO2H nanocatalyst in this project. In this study, the synthesis of the nanocatalyst (Fe3O4@NFC@NSalophCu)CO2H was explained in a step-by-step manner. Confirmation of the structure was obtained based on FT-IR, EDX, FE-SEM, TEM, XRD, VSM, DLS, TGA, H-NMR, and CHNO analyses. The catalyst was applied to the synthesis of 5-substituted-1H-tetrazole and 1-substituted-1H-tetrazole derivatives through multi-component reactions (MCRs), and the performance was assessed. With advances in science and technology and increasing environmental pollution, the use of reagents and methods that are less dangerous for the environment has received much attention. Therefore, following green chemistry principles, with the help of the (Fe3O4@NFC@NSalophCu)CO2H salen complex as a nanocatalyst that is recyclable, cheap, safe, and available, the use of water as a green solvent, and reduced reaction times, the synthesis of tetrazoles can be achieved.

Synthesis, characterization and cytotoxicity evaluation of a novel magnetic nanocomposite with iron oxide deposited on cellulose nanofibers with nickel (Fe3O4@NFC@ONSM-Ni)

A heterogeneous, magnetically recoverable nanocomposite, Fe3O4@NFC@ONSM-Ni(ii) was prepared by immobilization of a novel Ni(ii) Schiff base complex on Fe3O4@NFC nanoparticles followed by treatment with melamine. This trinuclear catalyst has been characterized using several analytical techniques including FT-IR, TEM, Fe-SEM, EDX, DLS, ICP, TGA, VSM, and XRD. It was used as an efficient catalyst for one-pot solvent-free synthesis of 1,4-dihydropyridine and poly-hydro quinoline derivatives through Hantzsch reaction. This catalyst showed remarkable advantage over previously reported catalysts due to suitable conditions, short reaction time, high efficiency and lower catalyst load and timely recovery of the magnetic catalyst. Moreover, the effects of Fe3O4@NFC@ONSM-Ni(ii) nanoparticles on the in vitro proliferation of human leukemia cell line (k562) and human breast cancer cells (MDA-MB-231) were investigated. The results of MTT and Hochest assays suggested that the nanoparticles could effectively inhibit the proliferation of these cancer cells in a time- and concentration-dependent manner.

The catalytic influence of phosphotungstic acid-functionalized Fe3O4 MNPs blended with TiO2 on the synthesis of novel spiro-acridines and the evaluation of their medicinal potential through molecular docking studies

This manuscript describes an effective and rapid three-component synthesis of a novel series of spiro-acridine derivatives by integrating the pharmacologically dynamic hydantoin-phenytoin as the prime synthetic equivalent. The process was accelerated by Fe3O4@TiO2-PTA magnetic nanoparticles (MNPs), which acted as the heterogeneous catalytic system, under ultrasonic conditions. The reaction was performed in the green PEG-200 solvent under aerophilic conditions to obtain products with excellent yields. The characteristics of the synthesized magnetic nano-catalysts were corroborated through powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDAX), FT-IR, and VSM techniques. In addition, the structures of the synthesized compounds were ascertained on the basis of elemental analyses and spectro-analytical data (1H NMR, 13C NMR, and mass spectrometry). High yields, smaller E-factor, considerable atom economy, easy recovery, and recyclability of the catalyst and solvent are the captivating features of the developed protocol. Moreover, in view of the ongoing global research on COVID-19, herein, we tried to identify the potential sites of the synthesized moiety that can suitably fit the receptor sites of the main protease of SARS-CoV-2 (SARS-CoV-2 Mpro).

SO3H-functionalized Zeolite-Y as an Efficient Nanocatalyst for the Synthesis of Nbenzimidazole- 2-aryl-4-thiazolidinones and tri-substituted Imidazoles

BACKGROUND

SO3H-functionalized zeolite-Y was prepared and used as a catalyst for the synthesis of 2-aryl-N-benzimidazole-4-thiazolidinones and tri-substituted imidazoles at ambient conditions.

OBJECTIVE

The goals of this catalytic method include excellent yields and high purity, inexpensive procedure and ease of product isolation, the use of nontoxic and heterogeneous acid catalyst, shorter reaction times and milder conditions.

MATERIALS AND METHODS

NMR spectra were recorded on Brucker spectrophotometer using Me4Si as internal standard. Mass spectra were recorded on an Agilent Technology 5975C VL MSD with tripe-axis detector. FTIR spectra were obtained with KBr disc on a galaxy series FT-IR 5000 spectrometer. The surface morphology of nanostructures was analyzed by FE-SEM (EVO LS 10, Zeiss, Carl Zeiss, Germany). BET analysis were measured at 196 °C by a Japan Belsorb II system after the samples were vacuum dried at 150°C overnight.

RESULTS

The NSZ was characterized by FT-IR, FESEM, EDX, XRF, and BET. The catalytic activity of NSZ was investigated for synthesis of 1,3-tiazolidin-4-ones in H2O/Acetone at room temperature. Moreover, NSZ was used for synthesis of tri-substituted imidazoles at 60 °C via solvent-free condensation. Different kinds of aromatic aldehydes were converted to the corresponding of products with good to excellent yields.

CONCLUSION

Sulfonated zeolite-Y was as an efficient catalyst for the preparation of N-benzimidazole-2-aryl-1,3- thiazolidin-4-ones and 2,4,5-triaryl-1H-imidazoles. High reaction rates, elimination toxic solvent, simple experimental procedure and reusability of the catalyst are the important features of this protocol.

Catalytic hydrolysis of cellobiose using different acid-functionalised Fe3O4 magnetic nanoparticles

The present study demonstrated the preparation of three different acid-functionalised magnetic nanoparticles (MNPs) and evaluation for their catalytic efficacy in hydrolysis of cellobiose. Initially, iron oxide (Fe3O4)MNPs were synthesised, which further modified by applying silica coating (Fe3O4-MNPs@Si) and functionalised with alkylsulfonic acid (Fe3O4-MNPs@Si@AS), butylcarboxylic acid (Fe3O4-MNPs@Si@BCOOH) and sulphonic acid (Fe3O4-MNPs@Si@SO3H) groups. The Fourier transform infrared analysis confirmed the presence of above-mentioned acid functional groups on MNPs. Similarly, X-ray diffraction pattern and energy dispersive X-ray spectroscopy analysis confirmed the crystalline nature and elemental composition of MNPs, respectively. TEM micrographs showed the synthesis of spherical and polydispersed nanoparticles having diameter size in the range of 20-80 nm. Cellobiose hydrolysis was used as a model reaction to evaluate the catalytic efficacy of acid-functionalised nanoparticles. A maximum 74.8% cellobiose conversion was reported in case of Fe3O4-MNPs@Si@SO3H in first cycle of hydrolysis. Moreover, thus used acid-functionalised MNPs were magnetically separated and reused. In second cycle of hydrolysis, Fe3O4-MNPs@Si@SO3H showed 49.8% cellobiose conversion followed by Fe3O4-MNPs@Si@AS (45%) and Fe3O4-MNPs@Si@BCOOH (18.3%). However, similar pattern was reported in case of third cycle of hydrolysis. The proposed approach is considered as rapid and convenient. Moreover, reuse of acid-functionalised MNPs makes the process economically viable.

Core–shell structured magnetic mesoporous silica supported Schiff-base/Pd: an efficacious and reusable nanocatalyst

Preparation, characterization and catalytic application of a novel magnetic ordered mesoporous silica supported Schiff-base/Pd (Fe₃O₄@MCM-41-SB/Pd) are developed.

Adsorptive removal of endocrine disrupting compounds from aqueous solutions using magnetic multi-wall carbon nanotubes modified with chitosan biopolymer based on response surface methodology: Functionalization, kinetics, and isotherms studies

Recently, the presence of endocrine disrupting compounds in the environment has emerged as a global and ubiquitous problem. In this study, a novel synthesis of magnetically carbon nanotube modified with biological polymeric was successfully prepared. The effect of different parameters on the Bisphenol A (BPA) adsorption was studied. A prediction model for BPA adsorption was extended based on the Central Composite Design. Also, the prepared biopolymeric nanotubes were characterized by FT-IR, XRD, TEM, FE-SEM. The surface morphology of nanocomposite was observed, increased carbon nano tube size, and the levels after surface deposition were completely covered by chitosan proteins. The results of our experiments showed that optimum adsorption conditions was achieved at t = 76 min, BPA concentration 6.5 mg/L, adsorbent dosage 1 g/L and pH = 6.2.The data obtained in this study followed the Langmuir isotherm model and the pseudo-second order model. The maximum monolayer adsorption capacity of nanocomposite for BPA was 46.2 mg/g at 20 °C. This study showed that the adsorption of BPA onto nanocomposite was spontaneous and thermodynamically desirable.

Fe3O4/SO3H@zeolite-Y as a novel multi-functional and magnetic nanocatalyst for clean and soft synthesis of imidazole and perimidine derivatives

In this study, SO₃H@zeolite-Y was synthesized by the reaction of chlorosulfonic acid with zeolite-NaY under solvent-free conditions, which was then supported by Fe₃O₄ nanoparticles to give SO₃H@zeolite-Y (Fe₃O₄/SO₃H@zeolite-Y) magnetic nanoparticles. Several techniques were used to evaluate the physical and chemical characterizations of the zeolitic nanostructures. Fe₃O₄-loaded sulfonated zeolite was applied as a novel multi-functional zeolite catalyst for the synthesis of imidazole and perimidine derivatives. This efficient methodology has some advantages such as good to excellent yield, high purity of products, reusability of nanocatalyst, simple reaction conditions, environmental friendliness and an economical chemical procedure from the viewpoint of green chemistry.

Fe₃O₄/SO₃H@zeolite-Y was applied as a novel, effective and environmentally friendly magnetic nanocatalyst for the synthesis of imidazole and perimidine scaffolds.

Fe3O4@BNPs@SiO2–SO3H as a highly chemoselective heterogeneous magnetic nanocatalyst for the oxidation of sulfides to sulfoxides or sulfones

To achieve green chemistry goals and also to reduce the cost of catalysts as well as to avoid producing toxic wastes and show the importance of separation and recycling of catalysts from the reaction medium, in this work, we describe the preparation and characterization of magnetic acidic boehmite nanoparticles as a heterogeneous catalyst, which is called Fe₃O₄@BNPs@SiO₂–SO₃H. This catalyst works efficiently in the selective oxidation of sulfides to sulfoxides or sulfones in the presence of H₂O₂ as a green oxidant. It can easily be separated from the reaction medium by using an external magnet and it was recycled 6 times without loss of magnetic catalytic properties.

To achieve the green chemistry goals and importance of separation and recycling of catalyst from the reaction medium, Fe₃O₄@BNPs@SiO₂–SO₃H is introduced as a novel heterogeneous nanocatalyst for the oxidation of sulfides to sulfoxides or sulfones.

Magnetic Nano-Sized Solid Acid Catalyst Bearing Sulfonic Acid Groups for Biodiesel Synthesis

In our approach for magnetic iron oxide nanoparticles surface modification, the fabrication of an inorganic shell, consisting of silica by the deposition of preformed colloids onto the nanoparticle surface and functionalization of these particles, was realized. The magnetic nanoparticles, non-coated and coated with silica layer by Stöber method, are functionalized with chlorosulfonic acid. The magnetic nanoparticles (MNPs), in size of 10-13 nm, could be used as acid catalyst in biodiesel production and show superparamagnetic character. The prepared nanoparticles were characterized by different methods including XRD, EDX, FT-IR and VSM. The catalytic activity of the coated and non-coated solid acids was examined in palmitic acid-methanol esterification as an industrial reaction for biodiesel synthesis. Although thin silica layer results in only a minor obstacle with respect to magnetism, it can accelerate the mass transportation due to its relatively porous structure and magnetic core may be more stable in the acidic reaction medium by means of covering process. Accordingly, coating strategy can be efficient way for allowing applications of MNPs in acid catalyzed esterification.

Mannich base-connected syntheses mediated by ortho-quinone methides

This article provides an overview about specifically modified Mannich reactions where the process involves an ortho-quinone methide (o-QM) intermediate. The reactions are classified on the basis of the o-QM source followed by the reactant, e.g., the dienophile partner in cycloaddition reactions (C=C or C=N dienophiles) or by the formation of multicomponent Mannich adducts. Due to the important pharmacological activities of these reactive o-QM intermediates, special attention is paid to the biological activity of these compounds.

Ultrasonic-assisted environmentally-friendly synergetic synthesis of nitroaromatic compounds in core/shell nanoreactor: A green protocol

An efficient sonochemical protocol for the nitration of aromatic compounds was described in the presence of a catalytic amount of sulfuric acid-functionalized silica-based core/shell magnetic nanocomposite at room temperature in an eco-friendly and recyclable media, deep eutectic solvent (DES), based on choline chloride and urea. The particle size, morphology and elemental analysis of the core/shell nanocatalyst were carried out by TEM, SEM, EDX and XRD analyses. The nanocatalyst and DES were easily recovered from the reaction mixture quantitatively and reused several times.

An imidazolium based ionic liquid supported on Fe3O4@SiO2 nanoparticles as an efficient heterogeneous catalyst for N-formylation of amines

An ionic liquid supported on silica-coated ferrite nanoparticles as an efficient and reusable catalyst for N-formylation of amines.

Magnetic Fe3O4@silica sulfuric acid nanoparticles promoted regioselective protection/deprotection of alcohols with dihydropyran under solvent-free conditions

Protection (and deprotection) of hydroxyl groups via tetrahydropyranylation was carried out effectively using a catalytic amount of Fe3O4 supported silica sulphuric acid nanoparticles (Fe3O4@SiO2@SO3H) under solvent-free conditions.