Synthesis and characterization of Se doped Fe3O4 nanoparticles for catalytic and biological properties

In this study, Se-doped Fe₃O₄ with antibacterial properties was synthesized using by a coprecipitation method. The chemistry and morphology of the Se doped Fe₃O₄ nanocomposite were characterized by energy-dispersive X-ray spectroscopy, field-emission scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry, and Brunauer-Emmett-Teller spectroscopy. The antibacterial activity of the Fe₃O₄/Se nanocomposite was examined against G⁺ (Gram-positive) and G^- (Gram-negative) bacteria, in the order Staphylococcus aureus, Staphylococcus saprophyticus, Pseudomonas aeruginosa, Klebsiella pneumonia, and Escherichia coli, which are the most harmful and dangerous bacteria. Fe₃O₄/Se, as a heterogeneous catalyst, was successfully applied to the synthesis of pyrazolopyridine and its derivatives via a one-pot four-component reaction of ethyl acetoacetate, hydrazine hydrate, ammonium acetate, and various aromatic aldehydes. Fe₃O₄/Se was easily separated from the bacteria-containing solution using a magnet. Its admissible magnetic properties, crystalline structure, antibacterial activity, mild reaction conditions, and green synthesis are specific features that have led to the recommendation of the use of Fe₃O₄/Se in the water treatment field and medical applications. Direct Se doping of Fe₃O₄ was successfully realized without additional complicated procedures.

Facile synthesis of pyrazolopyridine pharmaceuticals under mild conditions using an algin-functionalized silica-based magnetic nanocatalyst (Alg@SBA-15/Fe3O4)†

Pyrazolopyridines are common scaffolds in various bioactive compounds, which have several therapeutic effects and unique pharmacological properties. In this study, we fabricated a novel environmentally friendly silica-based nanocomposite as a multifunctional catalytic system for the synthesis of pyrazolopyridine derivatives. This novel heterogeneous nanocomposite named Alg@SBA-15/Fe₃O₄ (Alg stands for alginic acid), was prepared in several steps. In this regard, SBA-15 was synthesized by the hydrothermal method. Next, it was magnetized by Fe₃O₄ nanoparticles via an in situ co-precipitation process. Then, SBA-15/Fe₃O₄ particles were functionalized with 3-minopropyltriethoxysilane (APTES). Afterward, Alg@SBA-15/Fe₃O₄ was obtained by a nucleophilic substitution reaction between SBA-15/Fe₃O₄–NH₂ and an as-synthesized methyl-esterified alginic. Different analyses such as Fourier-transform infrared (FTIR), energy-dispersive X-ray (EDX) spectroscopy, field-emission scanning-electron microscopy (FESEM), vibrating-sample magnetometer (VSM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and BET (Brunauer–Emmett–Teller) have been used to confirm the structure of the fabricated catalyst. The magnetic properties of the Alg@SBA-15/Fe₃O₄ catalytic system imparted by Fe₃O₄ MNPs enable it to be conveniently isolated from the reaction mixture by using an external magnet. According to the obtained results, the prepared nanocatalyst has high thermal stability and it lost approximately 26% of its weight up to 800 °C. Interestingly, a small amount of prepared nanocatalyst (0.02 g) has shown excellent catalytic performance in the synthesis of pyrazolopyridine derivatives (90–97%) in a short reaction time (20–30 min) at room temperature which can be attributed to its porous structure and large surface area, and the presence of many acidic and basic functional groups. In general, it can be argued that the Alg@SBA-15/Fe₃O₄ nanocomposite deserves more attention due to its non-toxicity, ease of preparation, good recyclability, and its high catalytic efficiency.

Pyrazolopyridines are common scaffolds in various bioactive compounds, which have several therapeutic effects and unique pharmacological properties.

Catalyst-free synthesis of tetrahydrodipyrazolopyridines via an one-pot tandem and green pseudo-six-component reaction in water

Background

A new, green and environmentally friendly protocol has been developed for the synthesis of tetrahydrodipyrazolopyridine derivatives. The structures of these products were determined in terms of melting point, FTIR, NMR and Mass spectroscopy.

Results

The tetrahydrodipyrazolopyridine derivatives were synthesized in water through a catalyst-free pseudo-six-component reaction of hydrazine hydrate, ethyl acetoacetate, ammonium acetate and aldehyde at room temperature.

Conclusions

This novel procedure has some advantages such as aqueous media, high yield and simple work-up.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13065-022-00802-4.

Access to molecular complexity. Multicomponent reactions involving five or more components

The evaluation of the significance of a chemical transformation addresses many factors, including such important characteristics as the number of chemical bonds formed in one step, the reaction time, labour intensity, the cost of reactants and catalysts and so on. The amount of waste produced in the reaction has also gained increasing importance in recent years. Multicomponent reactions (MCRs) occupy a special place as a synthetic tool in modern organic chemistry. These reactions allow the synthesis of target products with complex structures, minimizing labour costs. This review summarizes the literature on multicomponent reactions involving five or more components. The data in the review are classified according to the number of reactants participating in the reaction and the types of reactions. It is worth noting that in some cases, these transformations can be a part of a domino process, making this classification difficult, if not impossible. The structural diversity of the reaction products greatly increases with increasing number of components involved in the MCR, which becomes virtually unlimited when using combinations of MCRs. This review highlights the main trends of past decades in the field of MCRs. The last two decades have witnessed an explosive growth in the number of publications in this area of chemistry.

The bibliography includes 309 references.

A decennary update on applications of metal nanoparticles (MNPs) in the synthesis of nitrogen- and oxygen-containing heterocyclic scaffolds

Heterocycles have been found to be of much importance as several nitrogen- and oxygen-containing heterocycle compounds exist amongst the various USFDA-approved drugs. Because of the advancement of nanotechnology, nanocatalysis has found abundant applications in the synthesis of heterocyclic compounds. Numerous nanoparticles (NPs) have been utilized for several organic transformations, which led us to make dedicated efforts for the complete coverage of applications of metal nanoparticles (MNPs) in the synthesis of heterocyclic scaffolds reported from 2010 to 2019. Our emphasize during the coverage of catalyzed reactions of the various MNPs such as Ag, Au, Co, Cu, Fe, Ni, Pd, Pt, Rh, Ru, Si, Ti, and Zn has not only been on nanoparticles catalyzed synthetic transformations for the synthesis of heterocyclic scaffolds, but also provide an inherent framework for the reader to select a suitable catalytic system of interest for the synthesis of desired heterocyclic scaffold.

Urease covalently immobilized on cotton-derived nanocellulose-dialdehyde for urea detection and urea-based multicomponent synthesis of tetrahydro-pyrazolopyridines in water

The urease Schiff-base covalently bonded to the designed high-content nanocellulosedialdehyde (HANCD) prepared from cotton-derived nanocellulose (NC) via tandem acid-hydrolysis and periodate-oxidation reactions was termed HANCD@urease. No change in the aldehyde content of HANCD after Schiff-base bonding to urease and similarity in the relative enzyme activities for HANCD@urease and free enzyme supported that the preparation conditions for HANCD-loaded urease are mild enough to prevent denaturation of the enzyme. As the immobilized urease showed higher stability and reusability versus free enzyme, the HANCD@urease was efficiently used to determine the urea concentration in aqueous solutions and blood serum samples. Alternatively, the catalytic efficiency of the HANCD@urease was demonstrated for the production of ammonia from urea in the multicomponent synthesis of 3,5-dimethyl-4-aryl-1,4,7,8-tetrahydrodipyrazolo[3,4-b:4′,3′-e]pyridines (THPPs) in water. This new environment-friendly urea sensor showed 90% preservation of the enzyme activity after the six cycles of reuse in enzymatic reactions, while its catalytic activity in the reaction of benzaldehyde, hydrazine hydrate, and alkyl acetoacetate with urea instead of hygroscopic ammonium salts did not change significantly after the sixth run. Detection and production of ammonia by a bio-compatible sensor and catalyst under mild conditions are features of this new green protocol.

The urease Schiff-base covalently bonded to the designed high-content nanocellulosedialdehyde (HANCD) prepared from cotton-derived nanocellulose (NC) via tandem acid-hydrolysis and periodate-oxidation reactions was termed HANCD@urease.

A multicomponent, facile and catalyst-free microwave-assisted protocol for the synthesis of pyrazolo-[3,4-b]-quinolines under green conditions

A facile, swift and ecofriendly microwave-assisted multi-component/one-pot protocol is designed for the synthesis of novel pyrazolo-[3,4-b]-quinolines at ambient temperature in aqueous ethanol as a reaction medium. The 18 novel pyrazolo-[3,4-b]-quinoline derivatives were synthesized by fusion of chosen aryl aldehyde, dimedone and 5-amino-3-methyl-1-phenylpyrazole in excellent yields (91–98%). All the molecular structures were confirmed by ¹H-NMR, ¹⁵N-NMR, ¹³C-NMR, and HRMS data analysis. Operational simplicity, easy handling, one-step simple workup procedure, mild reaction conditions, short reaction time (≤10 min), high selectivity and no by-product formation are the striking features of the protocol.

A facile, swift and ecofriendly microwave-assisted multi-component/one-pot protocol is designed for the synthesis of novel pyrazolo-[3,4-b]-quinolines at ambient temperature in aqueous ethanol as a reaction medium.

Nano-colloidal silica-tethered polyhedral oligomeric silsesquioxanes with eight branches of 3-aminopropyltriethoxysilane as high-performance catalyst for the preparation of bis-thiazolidinones under ultrasonic conditions

We report a class of organic–inorganic hybrid material based on nano-colloidal silica-tethered polyhedral oligomeric silsesquioxanes with eight branches of 3-aminopropyltriethoxysilane [nano-colloidal silica@APTPOSS (a series of polyhedral oligomeric silsesquioxanes with eight branches of 3-aminopropyltriethoxysilane)]. It was characterized by 1H NMR spectroscopy, dynamic light scattering, scanning electron microscope, energy dispersive spectroscopy and thermogravimetric analysis. An easy and rapid method for the synthesis of bis-thiazolidinones has been presented by one-pot pseudo-five-component reaction of benzaldehydes, ethylenediamine and 2-mercaptoacetic acid using nano-colloidal silica@APTPOSS. The reusability of the catalyst and little catalyst loading, excellent yields, short reaction times, using the sonochemical procedure as a green process and an alternative energy source are some benefits of this method.

Synthesis of 4,4′-(arylmethylene)bis(3-carboxymethyl-1-phenyl-1H-pyrazol-5-ol)s using ionic liquid attached to colloidal silica nanoparticles in water

An efficient synthesis of 10 4,4′-(arylmethylene)bis(3-carboxymethyl-1-phenyl-1 H-pyrazol-5-ol)s, eight of which are novel, was achieved by a one-pot three-component reaction of phenylhydrazine, dimethyl acetylenedicarboxylate and an arylaldehyde using bis(1(3-methoxysilylpropyl)-3-methyl-imidazolium) copper tetrachloride tethered to colloidal silica nanoparticles as catalyst under microwave irradiation in water. The advantages of the present process are atom economy, high catalytic activity, excellent yields, short reaction times and utilisation of microwave heating as a clean procedure. The catalyst was recyclable.

Magnetically separable graphene oxide anchored sulfonic acid: a novel, highly efficient and recyclable catalyst for one-pot synthesis of 3,6-di(pyridin-3-yl)-1H-pyrazolo[3,4-b]pyridine-5-carbonitriles in deep eutectic solvent under microwave irradiation

A magnetic separable sulfonic acid catalyst was prepared and applied for the synthesis of 3,6-di(pyridin-3-yl)-1H-pyrazolo[3,4-b]pyridine-5-carbonitriles via three-component reaction of 1-phenyl-3-(pyridin-3-yl)-1H-pyrazol-5-amine, β-ketonitrile and aldehydes in DES.