Using COC(=O)c1nc(OC(C)=O)n(C(C)=O)c1C, O=C1CCC(=O)N1Br to produce COC(=O)c1nc(OC(C)=O)n(C(C)=O)c1CBr, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.