Using O=C(O)CCc1ccc(Oc2ccc(O)cc2)cc1, OCCc1ccc(O)cc1 to produce O=C(CCc1ccc(Oc2ccc(O)cc2)cc1)OCCc1ccc(O)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.