Using COc1cccc2c1C(=O)c1ccccc1C2(CC(=O)O)CC(=O)O to produce COc1cccc2c1Cc1ccccc1C2(CC(=O)O)CC(=O)O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.