in n-heptane; water

toluene-4-sulfonic acid in water 5 h; Heating; Yield given;

1: p-toluenesulfonic acid / H2O / 5 h / Heating 2: acetic anhydride / 2 h / Heating 3: 94 percent / ethanol / 1 h / Ambient temperature 4: 84 percent / potassium carbonate / dimethylformamide / 2 h / 140 - 150 °C 5: 98 percent / conc. H2SO4 / H2O; acetic acid / 1.5 h / Heating View Scheme

1: p-toluenesulfonic acid / H2O / 5 h / Heating 2: acetic anhydride / 2 h / Heating 3: 94 percent / ethanol / 1 h / Ambient temperature 4: 84 percent / potassium carbonate / dimethylformamide / 2 h / 140 - 150 °C View Scheme

Multi-step reaction with 3 steps 1: p-toluenesulfonic acid / H2O / 5 h / Heating2: acetic anhydride / 2 h / Heating3: 94 percent / ethanol / 1 h / Ambient temperature