Using CCOC(C)=O, CC(=O)C1CCN(C(=O)OC(C)(C)C)CC1 to produce CC(=O)CC(=O)C1CCN(C(=O)OC(C)(C)C)CC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.