1,3-benzenediol, 5-[6-hydroxy-5-(3-methyl-2-butenyl)-2-benzofuranyl]- 5-[6-hydroxy-5-(3-methylbut-2-en-1-yl)-1-benzofuran-2-yl]benzene-1,3-diol InChI=1/C19H18O4/c1-11(2)3-4-12-5-13-8-18(23-19(13)10-17(12)22)14-6-15(20)9-16(21)7-14/h3,5-10,20-22H,4H2,1-2H