Using O=C([O-])[O-], COc1ccc2c([N+](=O)[O-])c(-c3ccc(O)cc3)[nH]c(=O)c2c1 to produce COc1ccc2c([N+](=O)[O-])c(-c3ccc(OC(=O)OC(C)(C)C)cc3)[nH]c(=O)c2c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.