InChI=1S/C13H20N2O8/c1-23-11-7(14-4-10(18)19)2-13(22,6-17)3-8(11)15-9(5-16)12(20)21/h9,14,16-17,22H,2-6H2,1H3,(H,18,19)(H,20,21)/b15-8+