trichlorophosphate 1.) 75 deg C, 4 h, 2.) reflux, 16 h;;

1: 90 percent / NH3 / 18 h / Ambient temperature 2: 54 percent / triethylamine / dimethylformamide / 3 h / 130 - 150 °C 3: 15 percent / POCl3 / 1.) 75 deg C, 4 h, 2.) reflux, 16 h; View Scheme