InChI=1S/C23H20O6/c24-19-14-11-18(12-15-19)13-16-23(27)28-17-6-4-2-1-3-5-8-20-21(29-20)9-7-10-22(25)26/h11-16,20-21,24H,7-10,17H2,(H,25,26)/b16-13+