Using O=C(O)c1ccc(S(=O)(=O)n2c(=O)[nH]c3cc(Cl)ccc3c2=O)cc1O to produce O=C([O-])c1ccc(S(=O)(=O)n2c(=O)[nH]c3cc(Cl)ccc3c2=O)cc1O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.