N-heterocyclic carbene-Pd(II) complex based on theophylline supported on Fe3O4@SiO2 nanoparticles: Highly active, durable and magnetically separable catalyst for green Suzuki-Miyaura and Sonogashira-Hagihara coupling reactions

Fast synthesis of [1,2,3]-triazole derivatives on a Fe/Cu-embedded nano-catalytic substrate

Triazoles are biologically important compounds that play a crucial role in biomedical applications. In this study, we present an innovative and eco-friendly nanocatalyst system for synthesizing compounds via the click reaction. The system is composed of Arabic gum (AG), iron oxide magnetic nanoparticles (Fe3O4 MNPs), (3-chloropropyl) trimethoxysilane (CPTMS), 2-aminopyridine (AP), and Cu(i) ions. Using AP as an anchor for Cu(i) ions and Fe3O4 MNPs allows facile separation using an external magnet. The hydrophilic nature of the Fe3O4@AG/AP-Cu(i) nanocomposite makes it highly efficient in water as a green solvent. The highest reaction efficiency (95.0%) was achieved in H2O solvent with 50.0 mg of nanocatalyst for 60 min at room temperature. The reaction yield remained consistent for six runs, demonstrating the stability and effectiveness of the catalyst.

Ag NPs supported chitosan-agarose modified Fe3O4 nanocomposite catalyzed synthesis of indazolo[2,1-b]phthalazines and anticancer studies against liver and lung cancer cells

In this article we report a novel Ag NPs fabricated chitosan-agarose composite functionalized core-shell type Fe₃O₄ nanoparticle (Ag/CS-Agar@Fe₃O₄). The biogenic material was analyzed over a number of physicochemical methods like, FT-IR, FE-SEM, TEM, EDX, XRD, VSM and ICP-OES. In catalytic exploration we aimed the synthesis of diverse 2H-indazolo0-b]phthalazine-trione derivatives via one-pot three component coupling of phathalalhydrazide, dimedone and different aldehydes. It afforded good to excellent yields under solvent-less conditions. Robustness of the catalyst was justified by catalyst recyclability for consecutive 10 times, hot filtration and leaching tests. Again, biological activity of the material was evaluated by studying the antioxidant and cytotoxicity properties over lung and liver cancer cell lines. Antioxidant potential of Ag/CS-Agar@Fe₃O₄ was assessed by DPPH radical scavenging studies and the corresponding IC50 was found to be 96.57 μg/mL. Liver and lung cancer studies over Ag/CS-Agar@Fe₃O₄ was carried out by MTT assay against HepG2 and A549 cell lines. The corresponding IC50 values were found as 192.35 and 365.28 μg/mL respectively. % Cell viability of the nanomaterial decreased dose dependently over both the cell lines without any cytotoxicity on normal cell line. The results demonstrates Ag/CS-Agar@Fe₃O₄ nanocomposite to be an efficient chemotherapeutic drug against the lung and hepatocellular carcinoma cells.

Magnetically Recoverable Nanoparticulate Catalysts for Cross-Coupling Reactions: The Dendritic Support Influences the Catalytic Performance

Carbon-carbon cross-coupling reactions are among the most important synthetic tools for the preparation of pharmaceuticals and bioactive compounds. However, these reactions are normally carried out using copper, phosphines, and/or amines, which are poisonous for pharmaceuticals. The use of nanocomposite catalysts holds promise for facilitating these reactions and making them more environmentally friendly. In the present work, the PEGylated (PEG stands for poly(ethylene glycol) pyridylphenylene dendrons immobilized on silica loaded with magnetic nanoparticles have been successfully employed for the stabilization of Pd2+ complexes and Pd nanoparticles. The catalyst developed showed excellent catalytic activity in copper-free Sonogashira and Heck cross-coupling reactions. The reactions proceeded smoothly in green solvents at low palladium loading, resulting in high yields of cross-coupling products (from 80% to 97%) within short reaction times. The presence of magnetic nanoparticles allows easy magnetic separation for repeated use without a noticeable decrease of catalytic activity due to the strong stabilization of Pd species by rigid and bulky dendritic ligands. The PEG dendron periphery makes the catalyst hydrophilic and better suited for green solvents. The minor drop in activity upon the catalyst reuse is explained by the formation of Pd nanoparticles from the Pd2+ species during the catalytic reaction. The magnetic separation and reuse of the nanocomposite catalyst reduces the cost of target products as well as energy and material consumption and diminishes residual contamination by the catalyst. These factors as well as the absence of copper in the catalyst makeup pave the way for future applications of such catalysts in cross-coupling reactions.

Copper-free Sonogashira cross-coupling reactions: an overview

The Sonogashira reaction is a cross-coupling reaction of a vinyl or aryl halide with a terminal alkyne to form a C-C bond. In its original form, the Sonogashira reaction is performed with a palladium species as a catalyst while co-catalyzed by a copper species and a phosphine or amine. The reaction is conducted under mild conditions, i.e., room temperature, aqueous solutions, and the presence of mild bases. Undeniably, the Sonogashira reaction is among the most competent and efficient reactions widely used in organic synthesis. This named reaction has proved useful in many organic synthesis areas, including the synthesis of pharmaceuticals, heterocycles, natural products, organic compounds, complex molecules having biological activities, nanomaterials, and many more materials that we use in our daily lives. The presence of transition metals as a catalyst was indeed essential in the Sonogashira reaction. However, recently, the reaction has been successfully conducted without copper as a co-catalyst and phosphines or amines as bases. In this critical review, we have focused on developments in the Sonogashira reaction successfully performed in the absence of copper complexes, phosphines or amines, which could be of particular advantage in implementing green chemistry principles and making the reactions more achievable from an economic viewpoint.

Recent advances in NHC–palladium catalysis for alkyne chemistry: versatile synthesis and applications

This review summarizes the recent developments in NHC–palladium catalysis for alkyne chemistry: versatile synthesis and applications.

Suzuki–Miyaura cross coupling reaction: recent advancements in catalysis and organic synthesis

Suzuki–Miyaura cross coupling reaction (SMCR) – A milestone in the synthesis of C–C coupled compounds.

Immobilized Ag NPs on chitosan-biguanidine coated magnetic nanoparticles for synthesis of propargylamines and treatment of human lung cancer

The magnetically isolable nanobiocomposites have significant impact as the modified new generation catalysts in recent days. This has persuaded us to design and synthesis of a novel Ag NPs decorated biguanidine-chitosan (Bigua-CS) dual biomolecular functionalized core-shell type magnetic nanocomposite (Ag/Bigua-CS@Fe₃O₄). Bigua-CS could be introducing polysaccharide materials as potential coating agent to immobilizing and stabilizing metal nanoparticles. The material was characterized using several advanced techniques like fourier transformed infrared spectroscopy (FT-IR), inductively coupled plasma (ICP), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), atomic mapping, high resolution transmission electron microscopy (HR-TEM), vibrating sample magnetometer (VSM) and X-ray diffraction (XRD). Towards the chemical applications of the material, we headed the multicomponent synthesis of diverse propargylamines by A³ coupling in water, which ended up with excellent yields. Due to strong paramagnetism, the catalyst was easily isolable and reused in 9cycles without any leaching and considerable change in reactivity. In addition, the catalyst was engaged in biological assays like study of anti-oxidant properties by DPPH mediated free radical scavenging test using BHT as a reference molecule. Thereafter, on having a significant IC₅₀ value in radical scavenging assay, we extended the bio-application of the catalyst in anticancer study of adenocarcinoma cells of human lungs. The three different cancer cell lines, PC-14, LC-2/ad and HLC-1 were used in this regard. The best result was achieved in the case of PC-14 cell line with strong IC₅₀ values.

Decorated Au NPs on agar modified Fe3O4 NPs: Investigation of its catalytic performance in the degradation of methylene orange, and anti-human breast carcinoma properties

This work describes an eco-friendly approach for in situ immobilization of Au nanoparticles on the surface of Fe₃O₄ nanoparticles, with help of Agar and ultrasound irradiations, without using any toxic reducing and capping agents. The structure, morphology, and physicochemical properties were characterized by various analytical techniques such as Fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), inductively coupled plasma (ICP) and vibrating sample magnetometer (VSM). The desired catalyst showed great efficiency in the reductive degradation of methylene orange (MO) dye over NaBH₄ at room temperature. The MO was fully reduced in only 70 s and achieved rate constant of 9.6 × 10^-2 s^-1. The catalyst was reused for 10 runs without significant loss in catalytic activity. Cell viability of Fe₃O₄/agar/Au NPs was very low against breast adenocarcinoma (MCF7), breast carcinoma (Hs 578Bst), infiltrating ductal cell carcinoma (Hs 319.T), and metastatic carcinoma (MDA-MB-453) cell lines without any cytotoxicity on the normal cell line. According to the above findings, the Fe₃O₄/agar/Au NPs may be administrated for the treatment of several types of human breast carcinoma in humans.

Ag NPs on chitosan-alginate coated magnetite for synthesis of indazolo[2,1-b]phthalazines and human lung protective effects against α-Guttiferin

Biocomposite nanomaterials have been evolved as the new generation catalysts and therapeutic supplement in these days. Magnetically isolation has added new features to this category. This has encouraged us to synthesize a novel Ag NP adorned chitosan-alginate dual bio-polysaccharide (two of the more versatile polysaccharides) modified core-shell magnetic nanocomposite (Fe₃O₄/CS-Alg/Ag NPs). The material was meticulously characterized following different physicochemical techniques, such as, FT-IR, ICP-OES, FESEM, EDX, atomic mapping, TEM, VSM, XRD and XPS studies. The as synthesized material was catalytically explored in the one-pot multicomponent synthesis of biologically potent 2H-indazolo[2,1-b]phthalazine-trione derivatives involving a wide range of substrates. The reactions were ended up with excellent yields under solvent-free heating conditions. The catalyst recyclability, heterogeneity and leaching tests were performed to ensure its high stability and robustness. It could be reused as much as 10 times in succession with almost unchanged catalytic performances. In the lung protective part of the present research, the human lung toxicity was induced by α-Guttiferin. The cell viability of lung MRC-5, CCD19Lu, WI-38, and BEAS-2B cell lines was measured by trypan blue assay. Caspase-3 activity was assessed by the caspase activity colorimetric assay kit and mitochondrial membrane potential of lung cells was studied by Rhodamine123 fluorescence dye. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) test was used to show DNA fragmentation and apoptosis of lung cells. Also, the Rat inflammatory cytokine assay kit was used to measure the concentrations of inflammatory cytokines. The catalyst-treated cell cutlers significantly (p ≤ 0.01) reduced the DNA fragmentation, caspase-3 activity, and inflammatory cytokines concentrations, and raised the mitochondrial membrane potential and cell viability in the high concentration of α-Guttiferin-treated lung MRC-5, CCD19Lu, WI-38, and BEAS-2B cells. The best result of lung protective properties of catalyst against α-Guttiferin was seen in the high dose of catalyst i.e., 4 μg. DPPH test revealed similar antioxidant potentials for catalyst and butylated hydroxytoluene. The catalyst inhibited half of the DPPH molecules in the concentration of 171 μg/mL. According to the above results, catalyst can be administrated as a lung protective drug for the treatment of lung diseases after approving in the clinical trial studies in humans.

Porous organic polymer with in situ generated palladium nanoparticles as a phase-transfer catalyst for Sonogashira cross-coupling reaction in water

A new Pd nanoparticle loaded and imidazolium-ionic liquid decorated organic polymer of Pd@PTC-POP was readily fabricated via a Pd(PPh₃)₄ catalysed in situ one-pot Suzuki cross-coupling reaction between imidazolium attached dibromobenzene and 1,3,5-tri(4-pinacholatoborolanephenyl)benzene. Besides the high thermal and chemical stability, the obtained Pd@PTC-POP can be used as a highly active and reusable phase-transfer solid catalyst to promote the Sonogashira coupling reaction in water. The obtained results indicate that the Pd@PTC-POP herein could create a versatile family of solid phase transfer catalysts for promoting a broad scope of reactions carried out in water.

A Pd nanoparticle loaded and imidazolium-ionic liquid decorated organic polymer, which can be used as a highly active phase-transfer solid catalyst to promote the Sonogashira reaction in water, was reported.