Using O=C1C(O)=C2C(=Nc3ccccc3S2(=O)=O)c2ccccc21 to produce O=S1(=O)c2ccccc2Nc2c1c(O)c(O)c1ccccc21, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.