Using COc1ccc(-c2sc(C3OCCO3)c(-c3cccc(OC)c3)c2C)cc1 to produce COc1ccc(-c2sc(C=O)c(-c3cccc(OC)c3)c2C)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.