Using O=C1c2c(O)ccc([N+](=O)[O-])c2C(=O)c2c(O)ccc([N+](=O)[O-])c21 to produce O=C1c2ccccc2C(=O)c2ccccc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.