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