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