Using CCCc1c2ccccc2c(O)c2c(=O)cc(C(=O)[O-])oc12 to produce CCCc1c2ccccc2c(O)c2c(=O)cc(C(=O)O)oc12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.