Oxadiazole is a heterocyclic aromatic chemical compound with the molecular formula C₂H₂N₂O. There are four isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

s of oxadiazole:
1,2,4-Oxadiazole, 1,2,5-oxadiazole, and 1,3,4-oxadiazole are known, but the 1,2,3-isomer is unstable and reverts to the diazo

Diazo

Diazo refers to a type of organic compound called diazo compound that has two linked nitrogen atoms as a terminal functional group. The general formula is R2C=N2. The simplest example of a diazo compound is diazomethane...

ketone

Ketone

In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

 tautomer

Tautomer

Tautomers are isomers of organic compounds that readily interconvert by a chemical reaction called tautomerization. This reaction commonly results in the formal migration of a hydrogen atom or proton, accompanied by a switch of a single bond and adjacent double bond...

. The stable oxadiazoles appear in a variety of pharmaceutical drugs including raltegravir, butalamine

Butalamine

Butalamine is a vasodilator....

, fasiplon

Fasiplon

Fasiplon is a nonbenzodiazepine anxiolytic drug from the imidazopyrimidine family of drugs.Fasiplon binds strongly to benzodiazepine sites on the GABAA receptor and has similar anxiolytic effects in animals, but with less sedative or muscle relaxant action....

, oxolamine

Oxolamine

Oxolamine is a cough suppressant.-Synthesis:The syntheses of 1,2,4-oxadiazole systems all rely on hydroxylamine for providing a preformed N-O linkage...

, and pleconaril.