InChI=1S/C21H20O7/c1-4-8-15(23)27-19-14(25-2)11-13(22)16-17(24)21(26-3)18(28-20(16)19)12-9-6-5-7-10-12/h5-7,9-11,22H,4,8H2,1-3H3