InChI=1S/C14H12N2O4/c17-13(18)7-3-1-5-9-11(7)16-10-6-2-4-8(14(19)20)12(10)15-9/h1-5,8,12,15H,6H2,(H,17,18)(H,19,20)/t8-,12+/m1/s1