InChI=1S/C20H28O4/c1-6-11(2)19(22)24-18-17-12(3)10-23-16(17)9-14-7-8-15(21)13(4)20(14,18)5/h6,10,13-15,18,21H,7-9H2,1-5H3/b11-6+