Using COC(=O)c1cccc(COc2cc(C(=O)OC)cc(C(=O)OC)c2)c1 to produce O=C(O)c1cccc(COc2cc(C(=O)O)cc(C(=O)O)c2)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.