Using CCOCC(O)Cn1nc2c(-c3ccc(Cl)cc3)c(-c3ccc(Cl)cc3)cnn2c1=O to produce CCOCC(=O)Cn1nc2c(-c3ccc(Cl)cc3)c(-c3ccc(Cl)cc3)cnn2c1=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.