18642-23-4 3,9-Dihydroxy-2-(3-methyl-2-butenyl)-6H-benzofuro(3,2-c)(1)benzopyran-6-one 6H-Benzofuro(3,2-c)(1)benzopyran-6-one, 3,9-dihydroxy-2-(3-methyl-2-butenyl)- Psoralidin