InChI=1S/C15H16N2O7/c16-9-4-2-6-1-3-7(5-8(6)17-9)23-15-12(20)10(18)11(19)13(24-15)14(21)22/h1-5,10-13,15,18-20H,(H2,16,17)(H,21,22)