Using CCOC(=O)CC(Cc1nc(CO)co1)c1ccccc1, BrC(Br)(Br)Br to produce CCOC(=O)CC(Cc1nc(CBr)co1)c1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.