1: With hydrogenchloride; sodium nitrite 0.5 h; cooling; 2: With potassium iodide T=80°C; 2 h;

1.1: n-butyllithium / tetrahydrofuran; hexane / 0 °C 1.2: -78 - 20 °C 1.3: -78 - 20 °C 2.1: hydrogenchloride; water / 1,4-dioxane / 6 h / Reflux 3.1: sodium nitrite / 1,4-dioxane / -5 °C 3.2: -5 - 80 °C View Scheme

1.1: pyridine; 4-(N,N-dimethlyamino)pyridine / dichloromethane / 2 h / 0 °C 2.1: n-butyllithium / tetrahydrofuran; hexane / 0 °C 2.2: -78 - 20 °C 2.3: -78 - 20 °C 3.1: hydrogenchloride; water / 1,4-dioxane / 6 h / Reflux 4.1: sodium nitrite / 1,4-dioxane / -5 °C 4.2: -5 - 80 °C View Scheme

1.1: hydrogenchloride; water / 1,4-dioxane / 6 h / Reflux 2.1: sodium nitrite / 1,4-dioxane / -5 °C 2.2: -5 - 80 °C View Scheme

1.1: pyridine; 4-(N,N-dimethlyamino)pyridine / dichloromethane / 2 h / 0 °C 2.1: n-butyllithium / tetrahydrofuran; hexane / 0 °C 2.2: -78 - 20 °C 2.3: -78 - 20 °C 3.1: hydrogenchloride; water / 1,4-dioxane / 6 h / Reflux 4.1: sodium nitrite / 1,4-dioxane / -5 °C 4.2: -5 - 80 °C View Scheme