Using Br[Mg]c1ccccc1, O=C1CN2C(=O)C(=O)c3cccc(c32)N1 to produce O=C1CN2C(=O)C(O)(c3ccccc3)c3cccc(c32)N1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.