InChI=1S/C20H28O/c1-5-6-14-10-15-12-20(3,4)17-8-7-13(2)9-16(17)19(15)18(21)11-14/h9-11,16-17,21H,5-8,12H2,1-4H3/t16-,17-/m0/s1