Using COC(=O)c1cccc(Cn2c(=O)[nH]c(=O)c3ccccc32)c1 to produce O=C(O)c1cccc(Cn2c(=O)[nH]c(=O)c3ccccc32)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.