Four-component one-pot synthesis of unsymmetrical polyhydroquinoline derivatives using 3-methyl-1-sulfonic acid imidazolium hydrogen sulfate as a catalyst

A decennary update on applications of metal nanoparticles (MNPs) in the synthesis of nitrogen- and oxygen-containing heterocyclic scaffolds

Heterocycles have been found to be of much importance as several nitrogen- and oxygen-containing heterocycle compounds exist amongst the various USFDA-approved drugs. Because of the advancement of nanotechnology, nanocatalysis has found abundant applications in the synthesis of heterocyclic compounds. Numerous nanoparticles (NPs) have been utilized for several organic transformations, which led us to make dedicated efforts for the complete coverage of applications of metal nanoparticles (MNPs) in the synthesis of heterocyclic scaffolds reported from 2010 to 2019. Our emphasize during the coverage of catalyzed reactions of the various MNPs such as Ag, Au, Co, Cu, Fe, Ni, Pd, Pt, Rh, Ru, Si, Ti, and Zn has not only been on nanoparticles catalyzed synthetic transformations for the synthesis of heterocyclic scaffolds, but also provide an inherent framework for the reader to select a suitable catalytic system of interest for the synthesis of desired heterocyclic scaffold.

Dihydropyridines as potential α-amylase and α-glucosidase inhibitors: Synthesis, in vitro and in silico studies

Dihydropyridine derivatives 1-31 were synthesized via one-pot solvent free condition and screened for in vitro against α-amylase and α-glucosidase enzyme. The synthetic derivatives 1-31 showed good α-amylase inhibition in the range of IC₅₀ = 2.21 ± 0.06-9.97 ± 0.08 µM, as compared to the standard drug acarbose (IC₅₀ = 2.01 ± 0.1 µM) and α-glucosidase inhibition in the range of IC₅₀ = 2.31 ± 0.09-9.9 ± 0.1 µM as compared to standard acarbose (IC₅₀ = 2.07 ± 0.1 µM), respectively. To determine the mode of binding interactions of synthetic molecules with active sites of enzyme, molecular docking studies were also performed. Different spectroscopic techniques such as ¹H, ¹³C NMR, EI-MS, and HREI-MS were used to characterize all the synthetic compounds.

Green recipes to quinoline: A review

The quinoline core possesses a vast number of biological activities such as anticancer, antimalarial, antimicrobial, antifungal, antitubercular and antileishmanial. The conventional classical synthetic methods require the use of expensive and harsh conditions such as high temperature. Currently the scientific communities are searching new methodology to eliminate the use of chemicals, solvents and catalysts, which are hazardous to human health as well as to environment. This review provides a concise overview of new dimensions of green chemistry approaches in designing quinoline scaffold that would encourage the researchers towards green chemistry as well as future application of these greener, non-toxic, environment friendly methods in designing quinoline scaffold.

Ultrasonic-Assisted Preparation, Characterization, and Use of Novel Biocompatible Core/Shell Fe3O4@GA@Isinglass in the Synthesis of 1,4-Dihydropyridine and 4H-Pyran Derivatives

This work focussed on the synthesis of a new catalytic material isinglass (IG)-based Fe₃O₄@GA@IG core/shell magnetic nanoparticles and the investigation of its catalytic activity in two important multicomponent reactions. Fe₃O₄ nanoparticles were prepared using a simple coprecipitation method and then coated with IG consisting predominantly of the protein collagen in the presence of glutaraldehyde as a cross-linking agent. The obtained hybrid material has been characterized by Fourier transform infrared analysis, scanning electron microscopy, transmission electron microscopy (TEM), vibrating sample magnetometry, energy-dispersive X-ray, X-ray diffraction (XRD), and Brunauer-Emmett-Teller analyses. The results of XRD analysis implied that the prepared nanocomposite consists of two compounds of crystalline magnetite and amorphous IG, and the formation of its core/shell structure had been confirmed by TEM images. The catalytic performance of the as-prepared core/shell bionanocatalyst was evaluated for the first time in the synthesis of 1,4-dihydropyridine and 4H-pyran derivatives under sonication in ethanol. This core/shell structure because of the superparamagnetic property of Fe₃O₄ and unique properties of IG as a bifunctional biocatalyst offers a high potential for many catalytic applications. Recycling study revealed that no significant decrease in the catalytic activity was observed even after six runs.

Novel ionic liquid [2-Eim] HSO4 as a dual catalytic-solvent system for preparation of hexahydroquinolines under green conditions

A novel Brønsted acidic ionic liquid 2-ethylimidazolium hydrogen sulfate, [2-Eim] HSO₄, was synthesized.