Using CC(C)(C)OC(=O)N1CCOCC1C=O, CC1(C)OC(=O)CC(=O)O1 to produce CC(C)(C)OC(=O)N1CCOCC1CCC(=O)O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.