InChI=1S/C24H28N2O7/c1-32-20-15-16(5-9-18(20)27)6-11-21(29)25-13-3-4-14-26-22(30)12-8-17-7-10-19(28)24(33-2)23(17)31/h5-12,15,27-28,31H,3-4,13-14H2,1-2H3,(H,25,29)(H,26,30)/b11-6?,12-8+