InChI=1S/C20H17NO5/c1-3-12-26-17-10-8-14(13-18(17)25-2)9-11-19(22)21-16-7-5-4-6-15(16)20(23)24/h1,4-11,13H,12H2,2H3,(H,21,22)(H,23,24)/b11-9+