2H-1-benzopyran-5-ol, 7-(6-hydroxy-2-benzofuranyl)-2,2-dimethyl- 7-(6-hydroxy-1-benzofuran-2-yl)-2,2-dimethyl-2H-chromen-5-ol InChI=1/C19H16O4/c1-19(2)6-5-14-15(21)7-12(9-18(14)23-19)16-8-11-3-4-13(20)10-17(11)22-16/h3-10,20-21H,1-2H