InChI=1S/C21H18O5/c1-21(2)19(23)17-16-14(25-20(17)26-21)9-8-12-13(22)10-15(24-18(12)16)11-6-4-3-5-7-11/h3-10,17,19-20,23H,1-2H3/t17-,19-,20+/m1/s1