InChI=1S/C13H14N2O6/c14-10(16)6-5-9(13(20)21)15-11(17)7-3-1-2-4-8(7)12(18)19/h1-4,9H,5-6H2,(H2,14,16)(H,15,17)(H,18,19)(H,20,21)