63326-88-5 6H,7H-(1)Benzopyrano(4,3-b)(1)benzopyran-6-one, 7-(2-oxopropyl)- 7-(2-Oxopropyl)-6H,7H-(1)benzopyrano(4,3-b)(1)benzopyran-6-one 7-Acetonyl-6-oxo-6H,7H-1-benzopyrano(4,3-b)-1-benzopyran