Using CCOC(C)=O, CCOC(=O)c1nc(Br)cn1NC(=O)OC(C)(C)C to produce CCOC(=O)CC(=O)c1nc(Br)cn1NC(=O)OC(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.