Using Nc1cc(S(=O)(=O)[O-])cc2cc(S(=O)(=O)[O-])cc(S(=O)(=O)[O-])c12, O=C(OC(=O)c1ccc([N+](=O)[O-])cc1S(=O)(=O)O)c1ccc([N+](=O)[O-])cc1S(=O)(=O)O to produce O=C(Nc1cc(S(=O)(=O)[O-])cc2cc(S(=O)(=O)[O-])cc(S(=O)(=O)[O-])c12)c1ccc([N+](=O)[O-])cc1S(=O)(=O)O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.