Using CC(C)(C)OC(=O)N[C@@H](Cc1cn(C=O)c2ccccc12)C(=O)O, O=[N+]([O-])c1ccc(CBr)cc1 to produce CC(C)(C)OC(=O)N[C@@H](Cc1cn(C=O)c2ccccc12)C(=O)OCc1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.