Benzopyran

Benzopyran is an polycyclic organic compound that results from the fusion of a benzene ring to a heterocyclic pyran ring. According to IUPAC nomenclature it is called chromene. There are two isomers of benzopyran depending on the orientation of the fusion of the two rings, resulting in 1-benzopyran (chromene) and 2-benzopyran (isochromene). Each of these structures has further isomers depending on the position of the carbon that is fully saturated hence giving rise to 2H-1-benzopyran (2H-chromene) and 4H-1-benzopyran (4H-chromene).