1-ciano-1,2,3,4-tetraidro-5H-<1>benzopirano<3,4-c>piridin-2,4,5-trione
5-imino-5H-<1>benzopirano<3,4-c>piridin-2,4-dione
2-amino-3-carbetossi-4H-<1>benzopirano-4-cianacetato di etile
2,6-dioxo-4-(o-metossifenil)-3,5-dicianopiperidina
Cyano-(2-oxo-2H-chromen-4-yl)-acetic acid ethyl ester