4-Hydroxymethyl-4',5'-benzopsoralen , its CAS NO. is 123577-49-1, the synonyms are 4-(Hydroxymethyl)-2H-benzofuro(3,2-g)-1-benzopyran-2-one ; 2H-Benzofuro(3,2-g)-1-benzopyran-2-one, 4-(hydroxymethyl)- .