Using COC(=O)c1ccc(OC(=O)c2cc(=S(=O)=O)cco2)cc1OC to produce COc1cc(OC(=O)c2cc(=S(=O)=O)cco2)ccc1C(=O)O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.