triethylamine; trifluoroacetic anhydride in tetrahydrofuran T=0 - 20°C; 1.08333 h;

ammonia in 1,4-dioxane T=20°C; 0.75 h;

1.1: sodium hydroxide; water / tetrahydrofuran / 1.5 h 1.2: 1 h / pH 1.5 - 4 2.1: oxalyl dichloride / N,N-dimethyl-formamide / tetrahydrofuran / 3 h / 20 °C 3.1: ammonia / 1,4-dioxane / 0.75 h / 20 °C View Scheme

1.1: trichlorophosphate / 2 h / 117 °C / Cooling with ice 2.1: sodium hydroxide; water / tetrahydrofuran / 1.5 h 2.2: 1 h / pH 1.5 - 4 3.1: oxalyl dichloride / N,N-dimethyl-formamide / tetrahydrofuran / 3 h / 20 °C 4.1: ammonia / 1,4-dioxane / 0.75 h / 20 °C View Scheme

1.1: bromine; acetic acid / 15 h / 20 - 110 °C 1.2: 2 h / pH 4 2.1: trichlorophosphate / 2 h / 117 °C / Cooling with ice 3.1: sodium hydroxide; water / tetrahydrofuran / 1.5 h 3.2: 1 h / pH 1.5 - 4 4.1: oxalyl dichloride / N,N-dimethyl-formamide / tetrahydrofuran / 3 h / 20 °C 5.1: ammonia / 1,4-dioxane / 0.75 h / 20 °C View Scheme