InChI=1S/C15H20O4/c1-8(2)11-4-3-9(7-16)14-12(11)5-10(15(18)19)6-13(14)17/h5-6,8-9,11,16-17H,3-4,7H2,1-2H3,(H,18,19)/t9-,11+/m0/s1