in ethanol T=20°C;

1: 76 percent / POCl3 / Heating 2: ethanol / 20 °C View Scheme

1: hydrogenchloride; trifluoroacetic acid; sodium nitrite / water / 1 h / 20 °C 2: trichlorophosphate / 3 h / Reflux 3: triethylamine / dichloromethane / 20 °C View Scheme

1.1: hydrogenchloride / water / Reflux 2.1: diethyl ether / 1 h / 100 °C 2.2: 3 h / 50 - 110 °C 2.3: 3 h / 50 - 110 °C 3.1: hydrogenchloride; trifluoroacetic acid; sodium nitrite / water / 1 h / 20 °C 4.1: trichlorophosphate / 3 h / Reflux 5.1: triethylamine / dichloromethane / 20 °C View Scheme

1.1: nitric acid; acetic anhydride / dichloromethane 2.1: hydrogenchloride / water / Reflux 3.1: diethyl ether / 1 h / 100 °C 3.2: 3 h / 50 - 110 °C 3.3: 3 h / 50 - 110 °C 4.1: hydrogenchloride; trifluoroacetic acid; sodium nitrite / water / 1 h / 20 °C 5.1: trichlorophosphate / 3 h / Reflux 6.1: triethylamine / dichloromethane / 20 °C View Scheme

1.1: triethylamine / dichloromethane 2.1: nitric acid; acetic anhydride / dichloromethane 3.1: hydrogenchloride / water / Reflux 4.1: diethyl ether / 1 h / 100 °C 4.2: 3 h / 50 - 110 °C 4.3: 3 h / 50 - 110 °C 5.1: hydrogenchloride; trifluoroacetic acid; sodium nitrite / water / 1 h / 20 °C 6.1: trichlorophosphate / 3 h / Reflux 7.1: triethylamine / dichloromethane / 20 °C View Scheme

1.1: diethyl ether / 1 h / 100 °C 1.2: 3 h / 50 - 110 °C 1.3: 3 h / 50 - 110 °C 2.1: hydrogenchloride; trifluoroacetic acid; sodium nitrite / water / 1 h / 20 °C 3.1: trichlorophosphate / 3 h / Reflux 4.1: triethylamine / dichloromethane / 20 °C View Scheme