A CMC-g-poly(AA-co-AMPS)/Fe3O4 hydrogel nanocomposite as a novel biopolymer-based catalyst in the synthesis of 1,4-dihydropyridines

A CMC-g-poly(AA-co-AMPS)/Fe₃O₄ hydrogel nanocomposite was successfully designed and prepared via graft copolymerization of AA and AMPS on CMC followed by the cross-linking addition of FeCl₃/FeCl₂. The synthesized hydrogel nanocomposite was characterized by Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, elemental mapping, thermogravimetric analysis/differential thermal analysis (TGA/DTA), and vibrating sample magnetometry (VSM). The CMC-g-poly(AA-co-AMPS)/Fe₃O₄ hydrogel nanocomposite was employed as a biocompatible catalyst for the green synthesis of 1,4-dihydropyridine (1,4-DHP) derivatives under thermal and ultrasound-assisted reaction conditions. High efficiency, low catalyst loadings, short reaction time, frequent catalyst recovery, environmental compatibility and mild conditions were found in both methods.

One-pot multicomponent synthesis of benzophenazine tethered tetrahydropyridopyrimidine derivatives

A simple, facile, and efficient green methodology has been developed for the synthesis of benzophenazine tethered tetrahydropyridopyrimidine derivatives by the one-pot four-component reaction of cinnamaldehyde/crotonaldehyde, 2-hydroxy-1,4-naphthoquinone, 1,3-dimethyl-6-amino uracil, and o-phenylenediamine in ethanol medium under reflux conditions using p-TSA as a catalyst. In this environmentally benign methodology, three C-N and two C-C bonds are formed in one pot. The hybrid products have three bioactive moieties such as benzophenazine, tetrahydropyridine, and pyrimidine. Operational simplicity, metal-free conditions, wide substrate scope, readily available starting materials, moderate to good yields of the desired products, presence of pharmaceutically active moieties, and easy purification process are the notable features of this methodology.

PANI-Fe3O4@ZnO nanocomposite as magnetically recoverable organometallic nanocatalyst promoted synthesis of new Azo chromene dyes and evaluation of their antioxidant and antimicrobial activities

A new series of azo chromene dyes were synthesized via a facile cyclocondensation reaction of (E)-1,2-diphenyl-1-diazene and 4-aminocoumarin with 1:2 molar ratio catalyzed by the polyaniline-Fe₃O₄@ZnO nanocomposite (PANI-Fe₃O₄@ZnO). The salient features of this protocol lie in simple experimental procedure, moderate reaction conditions, and uses PANI-Fe₃O₄@ZnO nanocomposite as a magnetically separable heterogeneous catalyst. Two well-known methods were employed for assessing the antioxidant abilities of the target compounds, including free radical trapping of 2,2-diphenyl-1-picrylhydrazyl (DPPH), as well as ferric reducing antioxidant power assay. Also, several synthesized compounds were screened for their in vitro antimicrobial activities by employing the disk diffusion test on Gram-negative as well as Gram-positive bacteria.