Using CCOC(=O)C(C)Br, S=c1ncn(-c2ccc(Cl)c(Cl)c2)[nH]1 to produce CCOC(=O)C(C)Sc1ncn(-c2ccc(Cl)c(Cl)c2)n1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.