InChI=1S/C20H20O5/c1-12(2)3-7-15-18(23)10-8-16(20(15)25)17(22)9-5-13-4-6-14(21)11-19(13)24/h3-6,8-11,21,23-25H,7H2,1-2H3/b9-5+