Using O=[N+]([O-])[N+](=O)[O-], O=C(O)c1ccc(-c2ccc3occ(-c4ccccc4)c3c2)cc1 to produce O=C(O)c1ccc(-c2ccc3oc([N+](=O)[O-])c(-c4ccccc4)c3c2)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.