Ferrocene-Containing Ionic Liquid Supported on Silica Nanospheres (SiO2@Imid-Cl@Fc) as a Mild and Efficient Heterogeneous Catalyst for the Synthesis of Pyrano[3,2-b]Pyran Derivatives Under Ultrasound Irradiation

Recent developments using malononitrile in ultrasound-assisted multicomponent synthesis of heterocycles

Ultrasonic irradiation serves as a vigorous and environmentally sustainable approach for augmenting multicomponent reactions (MCRs), offering benefits such as thermal enhancement, agitation, and activation, among others. Malononitrile emerges as a versatile reagent in this context, participating in a myriad of MCRs to produce structurally diverse heterocyclic frameworks. This review encapsulates the critical role of malononitrile in the sonochemical multicomponent synthesis of these heterocyclic structures. The paper further delves into the biochemical and pharmacological implications of these heterocycles, elucidating their reaction mechanisms as well as delineating the method's scope and limitations. We furnish an overview of the merits and challenges inherent to this synthetic approach and offer insights for potential avenues in future research.

Ultrasound-assisted synthesis of kojic acid-1,2,3-triazole based dihydropyrano[3,2-b]pyran derivatives using Fe3O4@CQD@CuI as a novel nanomagnetic catalyst

The magnetic nanoparticles coated with carbon quantum dot and copper (I) iodide (Fe₃O₄@CQD@CuI) were used as eco-friendly heterogeneous Lewis / Brønsted acid sites and Cu (I) nanocatalysts. In the first step, it was applied in the synthesis of kojic acid-based dihydropyrano[3,2-b]pyran derivatives in a three-component reaction and in the second step, as a recyclable catalyst for the synthesis of kojic acid-1,2,3-triazole based dihydropyrano[3,2-b]pyran derivatives in the CuI-catalyzed azide/alkyne cycloaddition (CuAAC) reaction. The catalyst was characterized fully by using the different techniques including fourier transform infrared spectroscopy (FT-IR), elemental mapping analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray spectroscopy (EDX), transmission electron microscopy (TEM), thermal gravimetric (TG) and value-stream mapping (VSM) methods. The final synthesized derivatives were identified by ¹H- and ¹³C-NMR spectroscopy.

Greener organic synthetic methods: Sonochemistry and heterogeneous catalysis promoted multicomponent reactions

Ultrasound is an essential technique to improve organic synthesis from the point of view of green chemistry, as it can promote better yields and selectivities, in addition to shorter reaction times when compared to the conventional methods. Heterogeneous catalysis is another pillar of sustainable chemistry being the recycling and reuse of the catalysts one of its great advantage. In the other hand, multicomponent reactions provide the synthesis of structurally diverse compounds, in a one-pot fashion, without isolation and purification of intermediates. Thus, the combination of these protocols has proved to be a powerful tool to obtain biologically active organic compounds with lower costs, time and energy consumption. Herein, we provide a comprehensive overview of advances on methods of organic synthesis that have been reported over the past ten years with focus on ultrasound-assisted multicomponent reactions under heterogeneous catalysis. In particular, we present pharmacologically important N- and O-heterocyclic compounds, considering their synthetic methods using green solvents, and catalyst recycling.

Synthesis of Magnetic Ferrocene-Containing Polymer with Photothermal Effects for Rapid Degradation of Methylene Blue

Photothermal materials are attracting more and more attention. In this research, we synthesized a ferrocene-containing polymer with magnetism and photothermal properties. The resulting polymer was characterized by Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Its photo-thermocatalytic activity was investigated by choosing methylene blue (MB) as a model compound. The degradation percent of MB under an irradiated 808 nm laser reaches 99.5% within 15 min, and the degradation rate is 0.5517 min⁻¹, which is 145 times more than that of room temperature degradation. Under irradiation with simulated sunlight, the degradation rate is 0.0092 min⁻¹, which is approximately 2.5 times more than that of room temperature degradation. The present study may open up a feasible route to degrade organic pollutants.

Functionalized Silicas for Metal-Free and Metal-Based Catalytic Applications: A Review in Perspective of Green Chemistry

Heterogeneous catalysis plays a key role in promoting green chemistry through many routes. The functionalizable reactive silanols highlight silica as a beguiling support for the preparation of heterogeneous catalysts. Metal active sites anchored on functionalized silica (FS) usually demonstrate the better dispersion and stability due to their firm chemical interaction with FSs. Having certain functional groups in structure, FSs can act as the useful catalysts for few organic reactions even without the need of metal active sites which are termed as the covetous reusable organocatalysts. Magnetic FSs have laid the platform where the effortless recovery of catalysts is realized just using an external magnet, resulting in the simplified reaction procedure. Using FSs of multiple functional groups, we can envisage the shortened reaction pathway and, reduced chemical uses and chemical wastes. Unstable bio-molecules like enzymes have been stabilized when they get chemically anchored on FSs. The resultant solid bio-catalysts exhibited very good reusability in many catalytic reactions. Getting provoked from the green chemistry aspects and benefits of FS-based catalysts, we confer the recent literature and progress focusing on the significance of FSs in heterogeneous catalysis. This review covers the preparative methods, types and catalytic applications of FSs. A special emphasis is given to the metal-free FS catalysts, multiple FS-based catalysts and magnetic FSs. Through this review, we presume that the contribution of FSs to green chemistry can be well understood. The future perspective of FSs and the improvements still required for implementing FS-based catalysts in practical applications have been narrated at the end of this review.

Synthesis and characterization of a novel Fe3O4@SiO2–BenzIm-Fc[Cl]/BiOCl nano-composite and its efficient catalytic activity in the ultrasound-assisted synthesis of diverse chromene analogs

A new magnetic nano-catalyst bearing ionic liquid, ferrocene and BiOCl was synthesized and its catalytic activities were evaluated in the synthesis of a wide variety of 2-amino-3-cyano-4H-chromene derivatives (54 compounds) under ultrasound irradiation.