Using O=C(OCc1ccc(CO)cc1COC(=O)c1ccccc1)c1ccccc1, BrC(Br)(Br)Br to produce O=C(OCc1ccc(CBr)cc1COC(=O)c1ccccc1)c1ccccc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.