1: hexamethylenetetramine / 1.) reflux, 24h, 2.) water, 60 deg C, 5h 2: 53 percent / BCl3 / CH2Cl2 / 3 h / Ambient temperature 3: 4 percent / LiI / hexamethylphosphoric acid triamide / 25 h / 100 °C View Scheme