Using Cc1cc(C)n(C)c1C(=O)c1ccc(Cl)cc1Cl, O=C(Cl)CCl to produce Cc1c(C(=O)CCl)c(C)n(C)c1C(=O)c1ccc(Cl)cc1Cl, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.