1: N,N-dimethyl-formamide With trichlorophosphate T=0°C; Vilsmeier Reaction; Inert atmosphere; 2: 3,4-Diethylpyrrole in dichloromethane T=20°C; 10 h; Inert atmosphere; 3: With sodium hydroxide in water T=20°C; 1 h;

1: With trichlorophosphate in dichloromethane; N,N-dimethyl-formamide T=20°C; 18.5 h; Inert atmosphere; 2: With potassium hydroxide in water T=20°C; 2.5 h; Inert atmosphere;

1.1: 4-(N,N-dimethlyamino)pyridine / dichloromethane / 6 h / 20 °C / |Inert atmosphere 2.1: potassium carbonate / tetrahydrofuran; ethanol / 72 h / 20 °C 3.1: sodium hydroxide / ethylene glycol / 1 h / |Reflux 4.1: trichlorophosphate / 0 °C / |Inert atmosphere 4.2: 10 h / 20 °C / |Inert atmosphere 4.3: 1 h / 20 °C View Scheme

1.1: potassium carbonate / tetrahydrofuran; ethanol / 72 h / 20 °C 2.1: sodium hydroxide / ethylene glycol / 1 h / |Reflux 3.1: trichlorophosphate / 0 °C / |Inert atmosphere 3.2: 10 h / 20 °C / |Inert atmosphere 3.3: 1 h / 20 °C View Scheme

1.1: sodium hydroxide / ethylene glycol / 1 h / |Reflux 2.1: trichlorophosphate / 0 °C / |Inert atmosphere 2.2: 10 h / 20 °C / |Inert atmosphere 2.3: 1 h / 20 °C View Scheme

potassium hydroxide in dimethyl sulfoxide 14 h; Ambient temperature;

in ethanol Heating;

1: 61 percent / aq. NaOH / ethanol / 20 h / Heating 2: 90 percent / anhyd. HCl / diethyl ether / 25 h / Ambient temperature View Scheme

1: 86 percent / HBr / ethanol; diethyl ether / -10 °C 2: 100 percent / NaBH4 View Scheme

1: 42 percent / aq. HBr / ethanol / 1 h 2: NaBH4 / ethanol / 1 h / Ambient temperature View Scheme