Using Cc1cc2cc(Cl)ccc2n1C(=O)OC(C)(C)C, O=C1CCC(=O)N1Br to produce CC(C)(C)OC(=O)n1c(CBr)cc2cc(Cl)ccc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.