1-Oxo-1H-phenalene-2,3-dicarbonitrile heteroaromatic scaffold: revised structure and mechanistic studies.

Synthesis of the originally proposed 8-oxo-8H-acenaphtho[1,2-b]pyrrol-9-carbonitrile led to a structural revision, and the product has now been identified as unknown compound 1-oxo-1H-phenalene-2,3-dicarbonitrile. The structural assignment was corroborated by detailed NMR studies and unambiguously confirmed by X-ray diffraction. A mechanism is proposed to explain the formation of this original heterocyclic scaffold. In addition, some new chemical transformations involving this compound are presented.