Using O=[N+]([O-])O, Cc1c(CC(=O)O)c2cccc3c2n1CCC3 to produce Cc1c(CC(=O)O)c2cc([N+](=O)[O-])cc3c2n1CCC3, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.