Oxadiazoles are a class of heterocyclic aromatic compounds with the molecular formula C2H2N2O, which have special biological activities and thermodynamic properties. Five-membered heterocyclic moieties composed of three or two heteroatoms are of great interest to researchers because these compounds show significant therapeutic potential. These heterocycles can serve as a building block for the development of novel molecular structures.
Coumarin occurs naturally in a variety of plants, such as lentils, sweet sawdust, vanilla grass, and sweet grass. Coumarin has a simple structure, benzopyrone, associated with different reaction centers. Coumarins are further subdivided into different classes: simple coumarins, pyranocoumarins, furanocoumarins, dicoumarins and isocoumarins. Coumarin derivatives are an important class of natural plant metabolites with various biological activities. They can also be synthesized artificially, and various synthetic coumarin derivatives (azoles, sulfonyls, furans, pyrazoles, etc.) have shown good anticancer, antitumor and antiproliferative activities. Coumarin derivatives are not only effective anticancer agents, but also possess minimum side effects. Based on different substitution patterns, these potential active substances show a great ability to modulate potential anticancer activities.
Isoxazole is a liquid heterocyclic compound C3H3NO isomeric with oxazole and having a penetrating odor like that of pyridine. Isoxazoles belong to an important class of five-membered aromatic heterocycles containing two electronegative heteroatoms, nitrogen and oxygen, in a 1,2-relationship and three regular sp2 carbon atoms. These molecules are found to be key components in various synthetic products in daily use and also present as a pharmacophore essential for biological activity in many drugs and bioactive natural products. In addition, isoxazoles have demonstrated their ability to exhibit hydrogen bond donor/acceptor interactions with a variety of enzymes and receptors.