InChI=1S/C20H20O4/c1-20(2)8-7-16-17(24-20)6-5-15(19(16)22)13-9-12-3-4-14(21)10-18(12)23-11-13/h3-8,10,13,21-22H,9,11H2,1-2H3/t13-/m0/s1