Using O=[N+]([O-])c1cccc(CNc2cccc(Nc3nc(Cl)ncc3Cl)c2)c1 to produce Nc1cccc(CNc2cccc(Nc3nc(Cl)ncc3Cl)c2)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.