Using COc1ccc(C(=O)c2ccc(OCC(=O)O)c(Cl)c2Cl)cc1 to produce O=C(O)COc1ccc(C(=O)c2ccc(O)cc2)c(Cl)c1Cl, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.