Using COc1ccc(CN2CC([Se]c3ccccc3)C(=O)N(c3cccc(Br)c3C)C2=O)cc1 to produce COc1ccc(Cn2ccc(=O)n(-c3cccc(Br)c3C)c2=O)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.