Using CN(CC(=O)C(Cc1ccccc1)NC(=O)c1ccccc1)C(=O)OCc1ccccc1 to produce CNCC(=O)C(Cc1ccccc1)NC(=O)c1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.