Using CNc1ccc(C(=O)NCC(=O)OC(C)(C)C)cc1[N+](=O)[O-] to produce CNc1ccc(C(=O)NCC(=O)O)cc1[N+](=O)[O-], please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.