Using O=C(O)[C@@H]1CCNC1, CC(C)(C)C1CCC(Oc2ccc3sc(C=O)nc3c2)CC1 to produce CC(C)(C)C1CCC(Oc2ccc3sc(CN4CC[C@@H](C(=O)O)C4)nc3c2)CC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.