1: 75 percent / K3<Fe(CN)6>, K2CO3 / H2O / 0.17 h 2: hexamethylenetetramine / 1.) reflux, 24h, 2.) water, 60 deg C, 5h 3: 53 percent / BCl3 / CH2Cl2 / 3 h / Ambient temperature 4: 4 percent / LiI / hexamethylphosphoric acid triamide / 25 h / 100 °C View Scheme