Advances in the greener synthesis of chromopyrimidine derivatives by a multicomponent tandem oxidation process

Abstract A hydrophilic cobalt/copper heterogeneous bimetallic catalyst named mTEG-CS-Co/Cu-Schiff-base/IL was successfully synthesized from chitosan polysaccharide. The new catalyst was investigated and confirmed using various techniques including FT-IR, FE-SEM, EDX-EDS, XRD, TEM, TGA, AFM, NMR and ICP. The catalyst exhibited powerful catalyst activity for the tandem one pot oxidative chromopyrimidine reaction from benzyl alcohols under mild conditions, utilizing air as a clean source in a green protocol. The catalyst was compatible with a wide range of benzyl alcohols, and aldehydes formed in situ, and bis-aldehydes synthesized were condensed with urea/4‑hydroxycumarin to provide favorable products in good yields for all derivatives (14 new derivatives). The presence of tri-ethylene glycol and imidazolium moieties with hydrophilic properties on the mTEG-CS-Co/Cu-Schiff-base/IL nanohybrid provides dispersion of the nanohybrid particles in water, leading to higher catalytic performance. Furthermore, the reaction exhibited several other notable features, including low catalyst loading, the ability to be recycled for up to 6 stages, high atom economy, a simple work procedure, short reaction time, utilization of an environmentally friendly nanohybrid, and the replacement of volatile and organic solvents with water solvent

Value-added synthesized acidic polymer nanocomposite with waste chicken eggshell: A novel metal-free and heterogeneous catalyst for Mannich and hantzsch cascade reactions from alcohols

The removal of metals from chemical reactions has raised growing concerns for conserving natural resources and environmental safety. Therefore, it is necessary to expand simple procedures that use eco-friendly materials with high elimination capacities. In this paper, we have synthesized a new nanocomposite material in which eggshell membranes act as nucleation sites for CoFe2O4 nanoparticle precipitation in the attendance of an external magnetic field. In the next step anchoring a chlorosulfonic acid on the surface of eggshell‐coated magnetic nanoparticles as solid waste was transformed into a magnetic biomaterial, green, cheap, and environmentally friendly catalyst (CoFe2O4@Eggshell@SO3H). Techniques such as FT-IR, VSM, FESEM, TEM, EDX, XRD, and TGA were used to characterize the as-synthesized catalyst. The catalytic property of the as-prepared catalyst was examined in the synthesis of 2,4,6-triarylpyridine, β-aminocarbonyl, and 2-amino-4,6-diphenylnicotinonitrile via alcohol-based oxidation. Excessive yield, quick reaction time, solvent-free condition, waste to wealth, and optimization with the layout of the experiment are the important advantages of the present work. Taken collectively, these results offer the conversion of wastage to fortune products around the world and utilization in organic metamorphosis

Loading of green-synthesized cu nanoparticles on Ag complex containing 1,3,5-triazine Schiff base with enhanced antimicrobial activities

Abstract The physicochemical properties of materials change significantly in nanometer dimensions. Therefore, several methods have been proposed for the synthesis of nanoparticles. Plant extracts and essential oils are applied as natural and economic resources to prepare nanomaterials especially metal nanoparticles. In this project, a green, simple and efficient method has been designed for the synthesis of Cu nanoparticles using Purple cabbage extract as a reducing and stabilizing agent. They were successfully loaded onto a new Ag complex containing 1,3,5-triazine Schiff base as ligand to form Cu@Ag-CPX nanocomposite. Phytochemical contents of extract were identified by standard qualitative analyses. The chemical structure of all synthesized compounds was characterized using spectral data. In FT-IR, coordination of C=N bond of Schiff base ligand to Ag+ ions shifted the absorption band from 1641 to 1632 cm−1. The UV–Vis spectrum of Cu@Ag-CPX nanocomposite shown the peak related to Cu nanoparticles in the region of around 251 nm. 5:7 molar ratio of Cu to Ag in Cu@Ag-CPX was determined using ICP-OES. The FESEM, TEM, and DLS techniques provided valuable insights into the morphology and size distribution of the nanocomposite, revealing the presence of rods and monodispersed particles with specific diameter ranges. These analyses of the nanocomposite displayed rods with diameters from 40 to 62 nm as well as monodispersed and uniform particles with average diameter of 45 nm, respectively. The presence of elements including carbon, nitrogen, oxygen, Cu and Ag was proved by EDX-EDS analysis. The XRD pattern of Cu@Ag-CPX shown the diffraction peaks of Cu and Ag particles at 2θ values of 10°–80°, and confirmed its crystalline nature. The inhibitory properties of the synthesized compounds were evaluated in vitro against four Gram-negative and two Gram-positive bacteria, as well as two fungal strains. The MIC, MBC and MFC values obtained from microdilution and streak plate sensitivity tests were ranged from 128 to 4096 µg ml−1. While Cu nanoparticles and Ag complexes were effective against some pathogens, they were not effective against all them. However, the growth of all tested microbial strains was inhibited by Cu@Ag-CPX nanocomposite, and makes it as a new promising antimicrobial agent. Modification of nanocomposite in terms of nanoparticle and complex can improve its blocking activities

Comparative study of antioxidant and antimicrobial activity of berberine-derived Schiff bases, nitro-berberine and amino-berberine

In recent years, the scientific community has focused on traditional natural products and their potential therapeutic benefits. Berberine is a plant-derived isoquinoline alkaloid with a variety of biological properties and identified as a promising pharmacophore for discovering new therapeutic agents against various diseases. However, unfavorable pharmacokinetic properties of berberine have limited its clinical application so much that researchers pursue its structure modification to overcome this problem. This study focuses on the synthesis of new berberine derivatives to improve its antioxidant and antimicrobial potentials, which were characterized using CHNO and NMR instruments. Berberine extracted from barberry root was nitrated, reduced to amine and condensed with benzaldehyde derivatives to produce berberine-based Schiff bases. The H atom donating ability of all compounds was measured against DPPH free radicals, with IC50 values ranging from 18.28 to 108.20 μg ml−1. All berberine-based Schiff bases exhibited stronger antioxidant activity than nitro-berberine and amino-berberine. Only Schiff base derived from 4-hydroxybenzaldehyde showed slightly better antioxidant effects than original berberine. The inhibitory effects of the synthesized compounds were evaluated against important pathogenic fungal and bacterial strains using disk diffusion assays, with inhibition zone diameters ranging from 8.36 to 25.48 μg ml−1. Berberine itself only affected Candida albicans fungus. Nitrated berberine was effective against all microorganisms except Gram-negative Acinetobacter baumannii. The results suggest that structural modifications and functionalization can enhance the antimicrobial and antioxidant properties of berberine