Using CCOC(=O)CC1(C(=O)OCC)CCN(C(=O)OC(C)(C)C)CCC1=O to produce CC(C)(C)OC(=O)N1CCC(=O)C(CC(=O)O)CC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.