Recent Progress in the Synthesis of Isoxazoles

Isoxazole derivatives are aromatic five-membered ring heterocyclic compounds with one oxygen atom and one nitrogen atom at adjacent positions. These compounds have a broad spectrum of applications in medicinal chemistry, such as antimicrobial, anticancer, antitumor, antitubercular, analgesic, anti-inflammatory, antidepressant, and anticonvulsant activities and some of them are well-known drugs for the treatment of various diseases in the market. The use of this class of compounds in agriculture as herbicides, insecticides have been widely reported. In organic materials, these compounds have been applied as semiconductors, single-walled nanotubes, liquid crystals, chiral ligands, scaffolds for peptidomimetics, dyes, and high-temperature lubricants. Isoxazole derivatives also play an important role in organic synthesis because they can be converted into several important synthetic units such as β-hydroxy ketones, γ -amino alcohols, α , β-unsaturated oximes, β -hydroxy nitriles, α-hydroxy-β-diketones, and β - dicarbonyl compounds. Due to such a wide range of applicability, the synthesis of isoxazole derivatives has attracted intensive research from chemists. This review will focus on considerable studies on the synthesis of isoxazoles which date back from 2012.