Oxadiazole

Oxadiazole is a heterocyclic aromatic chemical compound with the molecular formula C₂H₂N₂O. There are four isomers of oxadiazole:

1,2,3-oxadiazole

1,2,4-oxadiazole

1,2,5-oxadiazole
(furazan)

1,3,4-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 diazoketone tautomer. The stable oxadiazoles appear in a variety of pharmaceutical drugs including raltegravir, butalamine, fasiplon, oxolamine, and pleconaril.