1: With sulfuric acid; nitric acid in methanol T=20 - 50°C; Cooling with ice; 2: With potassium hydroxide in methanol T=20°C; 2 h; 3: With hydrogenchloride in methanol pH=2 - 3;

1.1: nitric acid; sulfuric acid / 1 h / 0 - 20 °C 2.1: hydrogen / 5 palladium on charcoal / methanol / 20 - 30 °C / 1500.15 Torr / Inert atmosphere 3.1: pyridine; 1-propanephosphonic acid cyclic anhydride / 2-methyl tetrahydrofuran / 8 h / 47.5 °C 4.1: sodium methylate / 2-methyl tetrahydrofuran; methanol / 1 h / 25 °C 4.3: 78 °C View Scheme

1: nitric acid; sulfuric acid / 1 h / 0 - 20 °C 2: hydrogen / 5 palladium on charcoal / methanol / 20 - 30 °C / 1500.15 Torr / Inert atmosphere View Scheme

sulfuric acid; nitric acid T=0 - 50°C; 2 h;

1: With sulfuric acid in dichloromethane T=-5 - 0°C; 2: With nitric acid in dichloromethane T=-5 - 0°C; Product distribution / selectivity;

sulfuric acid; nitric acid; sodium sulfate in hexane; water

1: With sulfuric acid; nitric acid in methanol T=20 - 50°C; Cooling with ice; 2: With potassium hydroxide in methanol T=20°C; 2 h; 3: With hydrogenchloride in methanol pH=2 - 3;

1: sulfuric acid; nitric acid; sodium sulfate / hexane; water 2: hydrogenchloride; KOH / methanol View Scheme

1: sulfuric acid; nitric acid; sodium sulfate / hexane; water 2: hydrogenchloride; KOH / methanol 3: ammonium formate / ethanol View Scheme