Using Clc1ncnc2[se]c3c(c12)CCCC3, Nc1cncc(Br)c1 to produce Brc1cncc(Nc2ncnc3[se]c4c(c23)CCCC4)c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.