Chitosan-encapsulated manganese ferrite particles bearing sulfonic acid group catalyzed efficient synthesis of spiro indenoquinoxalines

Functionalized chitosan-inspired (nano)materials containing sulfonic acid groups: Synthesis and application

Nature-inspired chitosan (CS) materials show a high potential for the design/fabrication of sustainable heterogeneous (nano)materials with extraordinary structural/physical features, such as superior biodegradability/biocompatibility, simplicity of chemical modification, environmental safety, high availability, cost-effectiveness, high electrochemical activity, good film-forming ability, and antioxidant, antimicrobial/antibacterial, and anticoagulant activities. Industrialization and growth of industrial wastes or by-products induce an increasing demand for the development of clean, low-cost, and renewable natural systems to minimize or eliminate the utilization of environmentally toxic compounds. The preparation of novel heterogeneous functionalized polysaccharide-inspired bio(nano)materials via chemical modifications of natural CS to improve its physicochemical/biochemical properties has recently become tremendously attractive for many researchers. The most abundantly available and cost-effective functionalized CS-inspired (nano)materials are considerably valuable in terms of the economic aspects of production of (nano)catalysts, (nano)hydrogels, (nano)composite/blend membranes, and thus their commercialization. In this respect, the preparation of functionalized CS-inspired (nano)materials containing -SO3H groups has been represented as a valid alternative to the homogenous unmodified biomaterials for various applications. Sulfonated derivatives of CS-inspired (nano)materials may possess huge surface areas, catalytic activity, adsorption, and biological/biomedical properties. This review article is aimed at the investigation of different methods and potential applications of sulfonated CS-inspired (nano)materials in catalysis, fuel cells, adsorption of ions, membranes, and biological applications.

Design, preparation and characterization of magnetic nanoparticles functionalized with chitosan/Schiff base and their use as a reusable nanocatalyst for the green synthesis of 1H-isochromenes under mild conditions

In this study, a Schiff base complex magnetic nanocatalyst was designed and prepared. The structure of the Fe3O4@CS-SB-CaMgFe2O4 nanocatalyst was characterized using FT-IR spectroscopy, XRD, VSM, FE-SEM, EDX, elemental mapping, BET, and TGA techniques. The synthesis of 1H-isochromene compounds has attracted the attention of chemists due to their biological and medicinal properties. The 1H-isochromene derivatives were synthesized in the presence of the Fe3O4@CS-SB-CaMgFe2O4 nanocatalyst with excellent efficiency and short reaction time as well as according to the rules of green chemistry. This reaction was carried out using Fe3O4@CS-SB-CaMgFe2O4 as a catalyst to develop a simple method with low activation energy at room temperature under optimal conditions. This catalyst provides a promising route for the synthesis of 1H-isochromene multiple times through its recyclability without significant loss of catalytic activity. This nanocatalyst possesses several advantages, including cost-effectiveness, facile separation, environmental friendliness, and recyclability, for the efficient production of 1H-isochromenes. The obtained compounds were further analyzed using spectroscopic techniques, such as melting point, FT-IR, 1H NMR, and 13C NMR analyses, to confirm their structures. The spectra of the synthesized compounds were recorded and analyzed, and a plausible mechanism for their synthesis was proposed. The characterization results and structural elucidation provide valuable insights into the preparation of these compounds.

An overview of quinoxaline synthesis by green methods: recent reports

Quinoxalines and their derivatives belong to an important class of bicyclic aromatic heterocyclic system, also known as benzopyrazines, containing a benzene ring and a pyrazine ring. They have attracted considerable attention over the years due to their potential biological and pharmaceutical properties. A wide range of synthetic strategies is reported in this significant area of research. The present review showcases recent research advances in the synthesis of quinoxaline derivatives following environmentally benign approaches.

Design, preparation, and characterization of CS/PVA/SA hydrogels modified with mesoporous Ag2O/SiO2 and curcumin nanoparticles for green, biocompatible, and antibacterial biopolymer film

One of the most significant factors affecting the rapid and effective healing of wounds is the application of appropriate wound dressings. In the present study, novel antibacterial wound dressings are fabricated that consist of Chitosan (CS)/Polyvinyl alcohol (PVA)/Sodium Alginate (SA), which are all biocompatible, functionalized with mesoporous Ag2O/SiO2 and curcumin nanoparticles as reinforcements. In this research nanocomposites are fabricated (0 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt% of Ag2O/SiO2). After the composition of nanocomposites using the cross-linked technique, Fourier Transform Infrared (FT-IR) spectroscopy is performed to confirm the functional groups that are added to the polymer at each step. X-ray diffraction (XRD) is done to show the crystallinity of Ag2O/SiO2. Field emission scanning electron microscopy (FE-SEM) studies are performed to demonstrate the morphology of the structure, Energy-dispersive X-ray spectroscopy (EDS) is done to examine the elements in the wound dressing and atomic force microscopy (AFM) study is performed to show surface roughness and pores. Then the nanocomposites with different weight percentages are cultured in three bacteria called Acinetobacter baumannii, Staphylococcus epidermidis, and Proteus mirabilis, all three of which cause skin infections. Finally, by performing the tensile test, the results related to the tensile strength of the wound dressings are examined. The results show that with the increase of Ag2O/SiO2, the mechanical properties, as well as the healing properties of the wound dressing, have increased significantly. Fabricating these nanocomposites helps a lot in treating skin infections.