Using O=C(NCc1cn(-c2ccc(-n3cccc(O)c3=O)cc2)nn1)c1ccc(Cl)s1, OCCBr to produce O=C(NCc1cn(-c2ccc(-n3cccc(OCCO)c3=O)cc2)nn1)c1ccc(Cl)s1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.