1: 62 percent / N,N-dimethylaniline, POCl3 / CHCl3 / 1.5 h / Heating 2: 84 percent / methanesulfonic acid / acetic acid / 8 h / Heating 3: methanol / 120 h / Ambient temperature View Scheme

1.1: trichlorophosphate / 1,2-dichloro-ethane / 90 °C 2.1: N,N-dimethyl-formamide / 4 h / Reflux 3.1: hydrazine hydrate / tetrahydrofuran / 24 h / 20 °C 3.2: 0.5 h / pH 3 4.1: 24 h / Reflux View Scheme

1: N,N-dimethylaniline, POCl3 / 1,2-dichloro-ethane / 0.5 h / Heating 2: 98 percent / BBr3 / CH2Cl2; 1,2-dichloro-ethane / 2 h / Heating 3: 72 percent / tetrahydrofuran; methanol / 88 h / 60 °C 4: 70 percent / N,N-diisopropylethylamine / 1,2-dichloro-ethane / 1.5 h / 60 °C View Scheme

trichlorophosphate in 1,2-dichloro-ethane T=90°C;