Using Clc1ncnc2[se]c3c(c12)CCCC3, Nc1cc(Cl)nc(Cl)c1 to produce Clc1cc(Nc2ncnc3[se]c4c(c23)CCCC4)cc(Cl)n1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.