Using COc1cc(Br)c(O)cc1C(=O)O, O=[N+]([O-])[O-] to produce COc1cc(Br)c(O)c([N+](=O)[O-])c1C(=O)O, please predict the solvent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.