Using O=[N+]([O-])O, COC(=O)C1(c2ccc(OC)cc2)CC1 to produce COC(=O)C1(c2ccc(OC)c([N+](=O)[O-])c2)CC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.