Using OC(c1ccc(Cl)cc1Cl)c1c[nH]c2ncc(Oc3ccccc3)cc12 to produce O=C(c1ccc(Cl)cc1Cl)c1c[nH]c2ncc(Oc3ccccc3)cc12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.