InChI=1S/C18H18O5S/c1-3-17(13-5-9-15(19)10-6-13)18(4-2)14-7-11-16(12-8-14)23-24(20,21)22/h4-12,19H,2-3H2,1H3,(H,20,21,22)/b18-17-