Using CCOC(=O)c1c(-c2ccc3c(c2)OCO3)c2ccccc2[nH]c1=O to produce O=C(O)c1c(-c2ccc3c(c2)OCO3)c2ccccc2[nH]c1=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.