Using COC1=C(OC)C(=O)C(Cc2cccc(C(=O)O)c2OC(C)=O)=C(C)C1=O to produce COC1=C(OC)C(=O)C(Cc2cccc(C(=O)O)c2O)=C(C)C1=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.