What is "azirine"

n. (context organic compound English) An unsaturated heterocycle containing two carbon atoms and one nitrogen atom

Azirines are three membered heterocyclic unsaturated (i.e. they contain a double bond) compounds containing a nitrogen atom and related to the saturated analogue aziridine. They are highly reactive yet have reported in a few natural products such as Dysidazirine. There are two isomers of azirine: 1H-azirines with a carbon-carbon double bond are not stable and rearrange to the tautomeric 2H-azirine, a compound with a carbon-nitrogen double bond. 2H-Azirines can be considered strained imines and are isolable.