Using C1CCOC1, O=c1[nH]nc2c(-c3ccc(Cl)cc3)c(-c3ccc(Cl)cc3)c(Cl)nn12 to produce O=c1[nH]n2c(=O)[nH]nc2c(-c2ccc(Cl)cc2)c1-c1ccc(Cl)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.