Using O=C1CCC(=O)N1Br, Cc1cc(Cl)c(C(=O)c2ccc(Cl)cc2)c(Cl)c1 to produce O=C(c1ccc(Cl)cc1)c1c(Cl)cc(CBr)cc1Cl, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.