Using O=C(Cl)C(Cl)(Cl)Cl, CCOC(=O)c1cccc2nc(C)cn12 to produce CCOC(=O)c1cccc2nc(C)c(C(=O)C(Cl)(Cl)Cl)n12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.