Using [N-]=[N+]=[N-], CCOC(=O)C1=C[C@@H](OS(C)(=O)=O)[C@@H](OS(C)(=O)=O)[C@H](OS(C)(=O)=O)C1 to produce CCOC(=O)C1=C[C@@H](N=[N+]=[N-])[C@H](OS(C)(=O)=O)[C@H](OS(C)(=O)=O)C1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.