The Catalysts-Based Synthetic Approaches to Quinolines: A Review.

The most common heterocyclic aromatic molecule with potential uses in industry and medicine is quinoline. Its chemical formula is C9H7N, and it has a distinctive double-ring structure with a pyridine moiety fused with a benzene ring. Various synthetic approaches synthesize quinoline derivatives. These approaches include solvent-free synthetic approach, mechanochemistry, ultrasonic, photolytic synthetic approach, and microwave and catalytic synthetic approaches. One of the important synthetic approaches is a catalyst-based synthetic approach in which different catalysts are used such as silver-based catalysts, titanium-based nanoparticle catalysts, new iridium catalysts, barium-based catalysts, iron-based catalysts, gold-based catalysts, nickel-based catalyst, some metal-based photocatalyst, α-amylase biocatalyst, by using multifunctional metal-organic framework-metal nanoparticle tandem catalyst etc. In the present study, we summarized different catalyst-promoted reactions that have been reported for the synthesis of quinoline. Hopefully, the study will be helpful for the researchers.