InChI=1S/C21H28O4/c1-12(9-19-21(25-19)14(3)11-20(22)23)7-8-17-13(2)10-18(24-6)16(5)15(17)4/h7-10,14,19,21H,11H2,1-6H3,(H,22,23)/b8-7+,12-9+