Using COC(=O)CC(=O)OC, O=[N+]([O-])c1cc(Cl)c(Cl)c([N+](=O)[O-])c1 to produce COC(=O)C(C(=O)OC)c1c(Cl)cc([N+](=O)[O-])cc1[N+](=O)[O-], please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.