InChI=1S/C21H24O4/c1-13(2)4-7-18-19(23)9-8-17(21(18)24-3)15-10-14-5-6-16(22)11-20(14)25-12-15/h4-6,8-9,11,15,22-23H,7,10,12H2,1-3H3