Using CCOC(=O)C1C(=O)CC(C)(O)C(C(=O)OCC)C1c1ccc2c(c1)OCO2 to produce O=C(O)CC(CC(=O)O)c1ccc2c(c1)OCO2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.