Using O=C1CCC(=O)N1Br, Cc1cc([N+](=O)[O-])c(Cl)cc1Cl to produce O=[N+]([O-])c1cc(CBr)c(Cl)cc1Cl, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.