Synthesis of target compounds 9‐13. Reagents and conditions: (a) appropriate piperazine, DMF, 80 °C; (b) H2, Raney Ni, DMF, rt; (c) 4‐chloro‐benzylamine, MW, neat, 120 °C; (d) 5% NaOH, EtOH, reflux; (e) 4‐chloro‐benzylchloride, K2
CO
3, DMF, 60 °C; (f) appropriate aryl‐sulfonylamide, EDAC, DMAP, dry DMF, 70 °C.