Using COc1ccc2c(=O)c3c(Cl)ccc([N+](=O)[O-])c3oc2c1 to produce O=c1c2ccc(O)cc2oc2c([N+](=O)[O-])ccc(Cl)c12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.