Using CCOC(=O)c1cc2cc(Cl)cc(C)c2n1C(=O)OC(C)(C)C, O=C1CCC(=O)N1Br to produce CCOC(=O)c1cc2cc(Cl)cc(CBr)c2n1C(=O)OC(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.