Using COc1c(OC)c([N+](=O)[O-])c2c(c1[N+](=O)[O-])COC2=O to produce COc1c(O)c([N+](=O)[O-])c2c(c1[N+](=O)[O-])C(=O)OC2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.