Using CCC1C(=O)c2c(cc(OCC(=O)O)c(Cl)c2Cl)C1C, ClCl to produce CCC1(Cl)C(=O)c2c(cc(OCC(=O)O)c(Cl)c2Cl)C1C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.