Using BrC(Br)(Br)Br, Cc1cc(CO)cc(C)c1OC(=O)CNCC(=O)OC(C)(C)C to produce Cc1cc(CBr)cc(C)c1OC(=O)CNCC(=O)OC(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.