InChI=1S/C16H16O4/c1-19-12-5-2-10-4-7-15(20-16(10)9-12)11-3-6-13(17)14(18)8-11/h2-3,5-6,8-9,15,17-18H,4,7H2,1H3/t15-/m0/s1