InChI=1S/C12H18O4/c1-2-3-4-9(13)12-8(7-11(15)16)5-6-10(12)14/h3-4,8-9,12-13H,2,5-7H2,1H3,(H,15,16)/b4-3-/t8-,9?,12+/m1/s1