c1cc(cc(c1)Cl)C(CC#N)c2c[nH]c3c2nc(nc3O)N 129444 Ki = 5 nM 12296 8 P23492 Purine nucleoside phosphorylase c1ccc(c(c1)CCP(=O)(O)O)Cn2cnc3c2nc(nc3O)N 192028 IC50 = 450 nM 12296 8 P23492 Purine nucleoside phosphorylase