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