Using Cc1c(Br)ccc(NC(=O)OC(C)(C)C)c1C(=O)O, BrCc1ccccc1 to produce Cc1c(Br)ccc(NC(=O)OC(C)(C)C)c1C(=O)OCc1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.