InChI=1S/C21H22O4/c1-24-17-8-4-15-6-10-21(25-2)19(12-15)18-11-14(5-9-20(18)23)3-7-16(22)13-17/h5-6,9-13,23H,3-4,7-8H2,1-2H3/b17-13-