InChI=1S/C15H20O4/c1-8-15-7-14(2,3)6-9(15)4-10(13(17)18)11(15)5-12(16)19-8/h4,8-9,11H,5-7H2,1-3H3,(H,17,18)/p-1/t8-,9+,11-,15+/m0/s1