Using O=[N+]=O, COC(=O)CC(C)(c1ccc(Cl)cc1)C(C)C to produce COC(=O)CC(C)(c1ccc(Cl)c([N+](=O)[O-])c1)C(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.