InChI=1S/C16H18O9/c1-23-9-5-2-8(3-6-9)4-7-10(17)24-16-13(20)11(18)12(19)14(25-16)15(21)22/h2-7,11-14,16,18-20H,1H3,(H,21,22)/b7-4+