InChI=1S/C15H20N2O8/c1-5(16)8(17)6-3-2-4-7(9(6)18)24-15-12(21)10(19)11(20)13(25-15)14(22)23/h2-4,10-13,15,18-21H,16-17H2,1H3,(H,22,23)/b8-5-