Using CCn1ncc2c(-c3ccc(Cl)nc3)c(CO)c(-c3ccccc3)nc21 to produce CCn1ncc2c(-c3ccc(Cl)nc3)c(C=O)c(-c3ccccc3)nc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.