InChI=1S/C28H22O6S/c29-23-16-22(15-14-19-8-3-1-4-9-19)26-25(18-23)33-28(20-10-5-2-6-11-20)27(26)21-12-7-13-24(17-21)34-35(30,31)32/h1-18,27-29H,(H,30,31,32)/b15-14+