Using O=C(Cc1ccc(OCc2ccccc2)c(OCc2ccccc2)c1)OCc1ccccc1 to produce O=C(O)Cc1ccc(OCc2ccccc2)c(OCc2ccccc2)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.