Using O=C(O)CCNC(=O)OCc1ccccc1, CC1(C)OC(=O)CC(=O)O1 to produce COC(=O)CC(=O)CCNC(=O)OCc1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.