Using CC(C)(C)OC(=O)NC1(C(=O)O)CC1, NCC(=O)c1ccc(Br)cc1 to produce CC(C)(C)OC(=O)NC1(C(=O)NCC(=O)c2ccc(Br)cc2)CC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.