1: 80 percent / potassium carbonate / dimethylformamide / 24 h / 23 °C 2: 95 percent / sodium hydroxide / ethanol / 0.25 h / Heating 3: 75 percent / 2M-sodium hydroxide, hydrogen peroxide / ethanol / 1 h / 65 °C 4: formamide / 1 h / 190 °C View Scheme