Using O=C(O)CC(CC(=O)O)C(=O)O, OC1CCCCC1 to produce O=C(CC(CC(=O)OC1CCCCC1)C(=O)OC1CCCCC1)OC1CCCCC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.