InChI=1S/C21H20O6/c1-21(2)19(27-21)11-25-14-8-17(24-3)20-15(23)10-16(26-18(20)9-14)12-4-6-13(22)7-5-12/h4-10,19,22H,11H2,1-3H3/t19-/m0/s1