InChI=1S/C21H18N2O7/c24-15-16(25)19(20(27)28)30-21(17(15)26)29-18-11-4-2-1-3-10(11)13-12-9(5-7-22-13)6-8-23-14(12)18/h1-8,15-19,21,24-26H,(H,27,28)