InChI=1S/C21H20O7/c1-11(2)8-9-27-13-6-4-12(5-7-13)19-18(25)17(24)16-14(22)10-15(23)20(26-3)21(16)28-19/h4-8,10,22-23,25H,9H2,1-3H3