Using O=C(O)c1ccccc1C1c2ccc(O)cc2Oc2cc(O)ccc21 to produce O=C([O-])c1ccccc1C1c2ccc(O)cc2Oc2cc(O)ccc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.