InChI=1S/C16H22O4/c1-14(2)6-10(18)8-5-9(17)13-16(12(8)19-14)7-11(16)15(3,4)20-13/h9,11,13,17H,5-7H2,1-4H3/t9-,11+,13-,16+/m0/s1