InChI=1S/C20H20O10/c21-12-7-10(8-13(22)14(12)23)2-1-9-3-5-11(6-4-9)29-20-17(26)15(24)16(25)18(30-20)19(27)28/h1-8,15-18,20-26H,(H,27,28)/b2-1+