Indoline is an aromatic heterocyclic organic compound with the chemical formula C8H9N. The compound is based on the indole structure, but the 2-3 bond is saturated. Indoles and their derivatives continue to inspire the development of synthetic organic chemistry even years after their discovery. The specific scaffold is a privileged structure and is ubiquitous in pharmaceuticals and biologically active compounds. Fused indolines as indole derivatives are of particular interest as they are often found in natural products and bioactives such as strychnine and tryptanthrins (alkaloids), mitosanes and mitosenes (antitumor activity) and isatisine (antiviral activity).
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.