Using OB(O)c1ccc(Cl)cc1, CSc1nc(Cl)c(-c2ccccc2)c(Cl)n1 to produce CSc1nc(Cl)c(-c2ccccc2)c(-c2ccc(Cl)cc2)n1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.