Using Nc1ccc(Br)cc1C(=O)O, CC(C)(C)OC(=O)OC(C)(C)C to produce CC(C)(C)OC(=O)Nc1ccc(Br)cc1C(=O)O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.