InChI=1S/C21H18O6/c1-23-15-6-4-11-7-13-9-25-21(22)19(13)17(18(11)20(15)24-2)12-3-5-14-16(8-12)27-10-26-14/h3-6,8,17H,7,9-10H2,1-2H3