Using OCc1ccc2c(c1)C1(c3ccccc3-2)c2ccccc2-c2ccc(CO)cc21 to produce O=Cc1ccc2c(c1)C1(c3ccccc3-2)c2ccccc2-c2ccc(C=O)cc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.