InChI=1S/C20H22O4/c1-23-11-13-9-15(22)10-18-16-3-2-4-17(16)19(24-20(13)18)12-5-7-14(21)8-6-12/h5-10,16-17,19,21-22H,2-4,11H2,1H3/t16-,17+,19+/m1/s1