Using O=C(O)CN(CCN(CC(=O)O)CC(=O)O)CC(=O)O to produce O=C([O-])CN(CCN(CC(=O)[O-])CC(=O)[O-])CC(=O)[O-], please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.