Using O=C(C[C@@H](CCCNC(=O)OCc1ccccc1)NC(=O)OCc1ccccc1)NCCNC(=O)OCc1ccccc1 to produce NCCC[C@@H](N)CC(=O)NCCN, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.