Try searching for...
SCFBio, IIT Delhi
Formula: C13H8O6S | Mol. Weight: 292.27 g/mol
IUPAC: (6-oxobenzo[c]chromen-3-yl) hydrogen sulfate
C1=CC=C2C(=C1)C3=C(C=C(C=C3)OS(=O)(=O)O)OC2=O