An immobilized Schiff base-Mn complex as a hybrid magnetic nanocatalyst for green synthesis of biologically active [4,3-d]pyrido[1,2-a]pyrimidin-6-ones.

The immobilization of metal ions on inorganic supports has garnered significant attention due to its wide range of applications. These immobilized metal ions serve as catalysts for chemical reactions and as probes for studying biological processes. In this study, we successfully prepared Fe3O4@SiO2@Mn-complex by immobilizing manganese onto the surface of magnetic Fe3O4@SiO2 nanoparticles through a layer-by-layer assembly technique. The structure of these hybrid nanoparticles was characterized by various analytical techniques, including Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), and inductively coupled plasma-optical emission spectrometry (ICP-OES). Fe3O4@SiO2@Mn-complex was successfully utilized in the synthesis of biologically active 7-aryl[4,3-d]pyrido[1,2-a]pyrimidin-6(7H)-one derivatives in an aqueous medium, providing environmentally friendly conditions. The desired products were manufactured in high yields (81-95%) without the formation of side products. The heterogeneity of the solid nanocatalyst was assessed using a hot filtration test that confirmed minimal manganese leaching during the reaction. This procedure offers numerous advantages, including short reaction times, the use of a green solvent, the ability to reuse the catalyst without a significant decrease in catalytic activity, and easy separation of the catalyst using an external magnet. Furthermore, this approach aligns with environmental compatibility and sustainability standards.

CoFe2O4@SiO2-NH2@MOF-5 magnetic nanocatalyst for the synthesis of biologically active quinazoline derivatives.

Metal-organic frameworks (MOFs) offered excellent catalytic activity due to their superior porosity, and high densities of catalytic sites in remarkable specific surfaces. In this research, we prepared a magnetic nanocomposite based on MOF-5 which is one of the prominent and practical structures that have been reported in many applications, and investigated the advantages of it as a catalyst. The multi-functional catalyst was prepared in five steps including (1) preparation of cobalt ferrite nanoparticles (CoFe2O4), (2) surface modification of cobalt ferrite using tetraethyl orthosilicate, (3) surface functionalization using 3-aminopropyl triethoxysilane, (4) preparation of MOF-5, (5) preparation of CoFe2O4@SiO2-NH2@MOF-5 nanocomposite. The resulting catalyst was evaluated by FTIR, FESEM, EDX, XRD, and VSM analyses. The CoFe2O4@SiO2-NH2@MOF-5 nanocomposite was applied as a catalyst for the quinazoline derivatives' synthesis. Various products were prepared with significant yields (90-98%) in short reaction times (20-60 min) without difficult work-up. In addition, the magnetic behavior of the catalyst allows it to be collected and recycled by a magnet and applied for six consecutive cycles without significantly reducing its efficiency. Quinazoline derivatives showed significant biological activities so their antioxidant activity was between 23.7% and 88.9% and their antimicrobial activity was in contradiction of E. coli, S. enterica, L. monocytogenes, S. aureus, and E. faecalis.

Magnetic poly(1,8-diaminonaphthalene)-nickel nanocatalyst for the synthesis of antioxidant and antibacterial isoxazole-5(4H)-ones derivatives.

A magnetic poly (1,8-diaminonaphthalene)-nickel (PDAN-Ni@Fe3O4) composite as a multifunctional nanocatalyst was prepared in several steps including (I) synthesis of poly (1,8-diaminonaphthalene) (PDAN), (II) modification of PDAN with NiSO4 (PDAN-Ni) and (III) preparation of magnetic nanocatalyst by iron (I and II) salts in the existence of PDAN-Ni complex (PDAN-Ni@Fe3O4). Fourier-transform infrared spectroscopy (FTIR), elemental analysis (CHNSO), vibrating-sample magnetometer (VSM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), field emission scanning electron microscope (FESEM), ultraviolet-visible (UV-vis), and thermogravimetric analysis (TGA) were applied to characterize the prepared nanocatalyst. The PDAN-Ni@Fe3O4 was applied as an environmentally friendly nanocatalyst for the isoxazole-5(4H)-ones synthesis via a one-pot reaction between aryl/heteroaryl aldehyde, hydroxylamine hydrochloride, and ß-ketoester. The nanocomposite was also used for the synthesis of some new alkylene bridging bis 4-benzylidene-3-methyl isoxazole-5(4H)-ones. The catalyst's reusability, and the antioxidant and antibacterial activities of both catalyst and products, were studied. Results showed that the nanocatalyst and isoxazole-5(4H)-ones have antioxidant activity of 75% and 92%, respectively. In addition, the antibacterial test showed that the nanocatalyst and isoxazole-5(4H)-ones have highly active versus Staphylococcus aureus and Escherichia coli bacteria. The reusability and stability of the nanocatalyst, a medium to higher product yield and conversion, a faster reaction time, and the use of green solvents were a few benefits of this study.

Carboxymethyl cellulose/starch/reduced graphene oxide composite as a pH-sensitive nanocarrier for curcumin drug delivery.

Nanocomposites are promising drug carriers to treat terminal cancers with few adverse effects. Herein, nanocomposite hydrogels composed of carboxymethyl cellulose (CMC)/starch/reduced graphene oxide (RGO) were synthesized via a green chemistry approach and then encapsulated in double nanoemulsions to act as pH-responsive delivery systems for curcumin, a potential antitumor drug. A water/oil/water nanoemulsion containing bitter almond oil served as a membrane surrounding the nanocarrier to control drug release. DLS and zeta potential measurements were used to estimate the size and confirm the stability of curcumin-loaded nanocarriers. The intermolecular interactions, crystalline structure and morphology of the nanocarriers were analyzed through FTIR spectroscopy, XRD and FESEM, respectively. The drug loading and entrapment efficiencies were significantly improved compared to previously reported curcumin delivery systems. In vitro release experiments demonstrated the pH-responsiveness of the nanocarriers and the faster curcumin release at a lower pH. The MTT assay revealed the increased toxicity of the nanocomposites against MCF-7 cancer cells compared to CMC, CMC/RGO or free curcumin. Apoptosis was detected in MCF-7 cells via flow cytometry tests. The results obtained herein support that the developed nanocarriers are stable, uniform and effective delivery systems for a sustained and pH-sensitive curcumin release.

Poly(aniline-co-melamine)@MnFe2O4 nanocatalyst for the synthesis of 4,4'-(arylmethylene) bis (1H-pyrazole-5-ol) derivatives, and 1,4- dihydropyrano[2,3-c]pyrazoles and evaluation of their antioxidant, and anticancer activities.

In this work, magnetic poly(aniline-co-melamine) nanocomposite as an efficient heterogeneous polymer-based nanocatalyst was fabricated in two steps. First, poly(aniline-co-melamine) was synthesized through the chemical oxidation by ammonium persulfate, then the magnetic nanocatalyst was successfully prepared from the in-situ coprecipitation method in the presence of poly(aniline-co-melamine). The resulting poly(aniline-co-melamine)@MnFe2O4 was characterized by FTIR, FESEM, XRD, VSM, EDX, TGA, and UV-vis analyses. The catalytic activity of poly(aniline-co-melamine)@MnFe2O4 was investigated in the synthesis of 4,4'-(arylmethylene)bis(1H-pyrazole-5-ol) derivatives, and new alkylene bridging bis 4,4'-(arylmethylene)bis(1H-pyrazole-5-ol) derivatives in excellent yields. The yield of 1,4-dihydropyrano[2,3-c]pyrazoles, 4,4'-(arylmethylene)bis(1H-pyrazol-5-ol), yields, and new alkylene bridging bis 4,4'-(arylmethylene)bis(1H-pyrazol-5-ol) derivatives were obtained 89%-96%, 90%-96%, and 92%-96%, respectively. The poly(aniline-co-melamine)@MnFe2O4 nanocatalyst can be recycled without pre-activation and reloaded up to five consecutive runs without a significant decrease in its efficiency. In addition, the antioxidant activity of some derivatives was evaluated by DPPH assay. Results showed that the maximum antioxidant activity of 4,4'-(arylmethylene)bis(1H-pyrazole-5-ol) derivatives and 1,4-dihydropyrano[2,3-c]pyrazoles were 75% and 90%, respectively. Furthermore, 4,4'-(arylmethylene)bis(1H-pyrazole-5-ol) derivatives and 1,4-dihydropyrano[2,3-c]pyrazoles showed good potential for destroying colon cancer cell lines. Consequently, the poly(aniline-co-melamine)@MnFe2O4 nanocomposite is an excellent catalyst for green chemical processes owing to its high catalytic activity, stability, and reusability.

Ionic Liquid-Assisted Fabrication of Bioactive Heterogeneous Magnetic Nanocatalyst with Antioxidant and Antibacterial Activities for the Synthesis of Polyhydroquinoline Derivatives.

Antibacterial materials have obtained much attention in recent years due to the presence of hazardous agents causing oxidative stress and observation of pathogens. However, materials with antioxidant and antibacterial activities can cause toxicity due to their low biocompatibility and safety profile, urging scientists to follow new ways in the synthesis of such materials. Ionic liquids have been employed as a green and environmentally solvent for the fabrication of electrically conductive polymers. In the present study, an antibacterial poly(p-phenylenediamine)@Fe3O4 (PpPDA@Fe3O4) nanocomposite was fabricated using [HPy][HSO4] ionic liquid. The chemical preparation of PpPDA@Fe3O4 nanocomposite was initiated through the oxidative polymerization of p-phenylenediamine by ammonium persulfate in the presence of [HPy][HSO4]. The PpPDA@Fe3O4 nanocomposite exhibited antibacterial properties against Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria. The PpPDA@Fe3O4 nanocomposite was employed as a heterogeneous nanocatalysis for one-pot synthesis of polyhydroquinoline derivatives using aromatic aldehyde, dimedone, benzyl acetoacetate, and ammonium acetate. Polyhydroquinoline derivatives were synthesized in significant yields (90-97%) without a difficult work-up procedure in short reaction times. Additionally, PpPDA@Fe3O4 nanocatalyst was recycled for at least five consecutive catalytic runs with a minor decrease in the catalytic activity. In this case, 11 derivatives of polyhydroquinoline showed in vitro antioxidant activity between 70-98%.

Superparamagnetic Poly(aniline-co-m-phenylenediamine)@Fe3O4 Nanocomposite as an Efficient Heterogeneous Catalyst for the Synthesis of 1H-pyrazolo[1,2-a]pyridazine-5,8-diones & 1H-pyrazolo[1,2-b]phthalazine-5, 10-diones Derivatives.

BACKGROUND: The use of polymer-based catalysts has increased because of their high potential application as an effective catalyst in organic reactions. They have benefits such as high efficiency and reactivity, simple separation, and safety compared to other heterogeneous catalysts. AIM AND OBJECTIVE: The objective of the current research is to prepare solid polymer-based catalysts, poly(aniline-co-m-phenylenediamine) (PAmPDA), and its superparamagnetic nanocomposite. Then, the catalytic activity of the resulting superparamagnetic nanocomposite was investigated in the synthesis of 1H-pyrazolo[1,2-b]phetalazine-5,10-diones and 1H-pyrazolo[1,2-a]pyridazine-5,8-dione derivatives. A series of some 1H-pyrazolo[1,2-b]phetalazine-5,10-diones and 1H-pyrazolo[1,2-a]pyridazine-5,8-dione derivatives was tested for its antibacterial properties against the Staphylococcus aureus and E. coli bacteria. MATERIALS AND METHODS: PAmPDA copolymer was synthesized in a 1:2 molar ratio of Ani to mPDA via radical oxidative polymerization at room temperature. Superparamagnetic PAmPDA@Fe3O4nanocompo-site was synthesized from a mixture of Fe(II), Fe(III) solution, and PAmPDA copolymer via the in-situ co-precipitation technique. 1H-pyrazolo[1,2-b]phetalazine-5,10-diones were synthesized via one-pot three-component condensation reaction of Phthalhydrazide, aromatic aldehyde derivatives, and malono-nitrile in the presence of PAmPDA under solvent-free conditions at 80 °C. The synthesis of 1H-pyrazolo[1,2-a]pyridazine-5,8-dione derivatives was carried out via a one-pot three-component condensa-tion reaction of maleic hydrazide, aromatic aldehyde derivatives, and malononitrile in the presence of PAmPDA under reflux conditions at EtOH/H2O 1:1. The antibacterial activity of some derivatives was tested against Gram-positive and Gram-negative bacteria. RESULTS: First, superparamagnetic PAmPDA@Fe3O4 nanocomposite was synthesized and characterized successfully, and then the resulting nanocatalyst was used for the synthesis of pyrazolo[1,2-b]phthalazine and pyrazolo[1,2-a]pyridazine. We obtained the maximum yield of the desired 1H-pyrazolo[1,2-b]phthalazine-5,10 dione derivatives with 0.05 g of catalyst at 80°C, under solvent free conditions, whereby the reaction was complete within 30 min. A wide range of 1H-pyrazolo[1,2-b]phthalazine-5,10 dione derivatives were synthesized in good to excellent yield. On the other hand, pyrazolo[1,2-a]pyridazine derivative was synthesized successfully in high yield using PAmPDA as a nanocatalyst. The antibacterial activity of some derivatives, according to the data (inhibition zone%), showed good ac-tivity against Staphylococcus aureus and E. coli. CONCLUSION: In this research, PAmPDA was used for mild preparation of 1H-pyrazolo [1,2-a]pyridazine-5,8-diones & 1H-pyrazolo[1,2-b]phetalazine-5,10-diones derivatives with excellent yields and short reac-tion times. The attractive features of this protocol are simple procedure, cleaner reaction, and the use of recyclable nanocatalyst. Satisfactory yields of products and easy workup make this a useful protocol for the green synthesis of this class of compounds. The antibacterial activity of some derivatives, according to the data (inhibition zone%), showed good activity against Staphylococcus aureus and E. coli.

Novel Biomass Derived from Grape Pomace Waste as an Efficient Nanocatalyst for the Synthesis of Dibenzoxanthene, Tetraketone, bis(indolyl)alkane and Chromene Derivatives and their Antimicrobial Evaluation.

BACKGROUND: Sulfonated carbon-based solid acids (CBSAs) have been reported as an efficient solid acid catalyst for many acid-catalyzed reactions. Furthermore, the use of carbon obtained from biomass waste has been explored and these materials showed a higher catalytic performance and higher stability compared to other solid acids. OBJECTIVE: Novel biomass carbon-based solid acids nanoparticles with high catalytic activity in organic transformation, such as Grape pomace waste-SO3H Nanoparticles (GPW-SO3H NPs), were successfully synthesized. MATERIALS AND METHODS: Grape pomace waste-SO3H Nanoparticles (GPW-SO3H NPs) were successfully synthesized. The grape pomace waste was dried in an oven at a temperature of 70°C and crushed to powder using an electric spice grinder. A mixture of powdered grape pomace waste (1 g) and concentrated sulfuric acid (>98%, 10 mL) was stirred at room temperature. Then, the resultant mixture was transferred into a 100 mL sealed Teflon-lined autoclave and kept at 180°C for 12 h. After cooling to room temperature, the resulting black solid was dried at 100°C in an oven under vacuum and the sulfonic acid-functionalized magnetic nanoparticles (Fe3O4@C-SO3H) were obtained. RESULTS AND DISCUSSIONS: The catalytic activity of GPW-SO3H was assessed through an easy and rapid protocol developed for the one-pot synthesis of 14-aryl-14-H-dibenzo [a,j]xanthene, arylmethylene [bis(3- hydroxy-2-cyclohexene-1-one)], bis(indolyl)alkane and 2-amino-4-aryl-7-hydroxy-4H-chromene-3-carbonitrile derivatives in excellent yields. The advantages of this method include use of waste material for catalyst synthesis, high yields, mild reaction conditions, uncomplicated work-up procedures, neutral conditions, and recoverable catalyst. CONCLUSION: We have shown that biomass-derived solid acids, prepared from grape pomace waste, serve as a non-toxic, inexpensive and a promising eco-friendly and novel carbon-based solid acid nanocatalyst for organic transformations.