Using CCOC(=O)C1=NOC(Cc2c[nH]c3ccccc23)(C(=O)OCC)C1 to produce O=C(O)C1=NOC(Cc2c[nH]c3ccccc23)(C(=O)O)C1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.