Oxazolines are five-membered heterocyclic compounds with one double bond. The double bond may be in one of three positions, so there may be three different oxazoline rings. The 2-oxazoline structure is the most common, and 3-oxazoline and 4-oxazoline exist mainly as laboratory research compounds. Oxazolines exist between oxazole and oxazolidine in terms of saturation.
Incorporation of heterocycles into drug molecules can enhance physical properties and biological activity. Oxadiazoles are a class of five-membered heterocycles containing one oxygen and two nitrogen atoms with special biological activity and thermodynamic properties. 1,2,4- and 1,3,4-oxadiazoles are widely used in the development of bioactive molecules, but 1,2,5-oxadiazoles (furazans) are used relatively sparingly. Compared with 1,2,4- and 1,3,4-isomers, 1,2,5-oxadiazole has unique physicochemical properties and electronic effects. The furazan ring has a strong inductive effect, comparable to that of trifluoromethyl or tetrazolyl. The unique properties of furoxan can confer specific pharmacological activities to drug-like molecules.