1: With potassium acetate; acetic anhydride in toluene 0.25 h; 2: With isopentyl nitrite in toluene T=85°C; 4 h;

1.1: phosphorus oxytribromide / 3 h / 140 °C / pressure vessel 2.1: hydrogenchloride; SnCl2·2H2O / water / 1 h / 40 °C 3.1: 4-(N,N-dimethlyamino)pyridine / 60 °C 4.1: sodium hydroxide / methanol / 0.5 h / 20 °C 5.1: acetic anhydride; potassium acetate / toluene / 0.25 h 5.2: 4 h / 85 °C View Scheme

1.1: nitric acid; sodium nitrite / water / -17 - 0 °C 2.1: nitric acid; sulfuric acid / 25 - 130 °C 3.1: phosphorus oxytribromide / 3 h / 140 °C / pressure vessel 4.1: hydrogenchloride; SnCl2·2H2O / water / 1 h / 40 °C 5.1: 4-(N,N-dimethlyamino)pyridine / 60 °C 6.1: sodium hydroxide / methanol / 0.5 h / 20 °C 7.1: acetic anhydride; potassium acetate / toluene / 0.25 h 7.2: 4 h / 85 °C View Scheme

1.1: nitric acid; sulfuric acid / 25 - 130 °C 2.1: phosphorus oxytribromide / 3 h / 140 °C / pressure vessel 3.1: hydrogenchloride; SnCl2·2H2O / water / 1 h / 40 °C 4.1: 4-(N,N-dimethlyamino)pyridine / 60 °C 5.1: sodium hydroxide / methanol / 0.5 h / 20 °C 6.1: acetic anhydride; potassium acetate / toluene / 0.25 h 6.2: 4 h / 85 °C View Scheme

1.1: hydrogenchloride; SnCl2·2H2O / water / 1 h / 40 °C 2.1: 4-(N,N-dimethlyamino)pyridine / 60 °C 3.1: sodium hydroxide / methanol / 0.5 h / 20 °C 4.1: acetic anhydride; potassium acetate / toluene / 0.25 h 4.2: 4 h / 85 °C View Scheme