Sydnone imine is a mesoionic heterocyclic aromatic chemical compound. Sydnone imine is the imine of sydnone where the keto functional group of sydnone (=O) has been replaced with an imine (=NH) group.
A sydnone imine substructure can be found in the drugs feprosidnine, mesocarb, molsidomine, ciclosidomine, and linsidomine.