Using COc1ccc(C(=O)O)cc1O, CCc1c(O)cc(O)cc1CC(=O)OC to produce CCc1c(O)cc(O)c(C(=O)c2ccc(OC)c(O)c2)c1CC(=O)OC, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.