Using CC(C)(C)OC(=O)NCC(=O)CCC(=O)O, CC(C)(C)OC(=O)CCO to produce CC(C)(C)OC(=O)CCOC(=O)CCC(=O)CNC(=O)OC(C)(C)C, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.