Using CCOC(C)=O, CC(C)(C)OC(=O)C1CCC(C(=O)O)CN1C(=O)OC(C)(C)C to produce CCOC(=O)CC(=O)C1CCC(C(=O)OC(C)(C)C)N(C(=O)OC(C)(C)C)C1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.