1: 91 percent / propan-2-ol / 4 h / 80 °C 2: 75 percent / H2 / Ranei nickel T-4 / dioxane; ethanol / 6 h / 60 °C 3: 86 percent / aq. 80percent acetic acid / 9 h / 50 °C 4: 61 percent / imidazole / CHCl3 / 48 h / Heating 5: 84 percent / silver trifluoromethanesulphonate, 1,1,3,3-tetramethylurea / CH2Cl2 / 10 h / Ambient temperature 6: liquid ammonia, sodium / tetrahydrofuran / 6 h / -78 °C View Scheme