InChI=1S/C20H18O6/c1-23-17-9-14-11(5-7-26-16(14)10-18(17)24-2)19(21)13-3-4-15-12(20(13)22)6-8-25-15/h3-4,6,8-11,22H,5,7H2,1-2H3