1: p-toluenesulfonic acid / H2O / 5 h / Heating 2: acetic anhydride / 2 h / Heating 3: 95 percent / ethanol / 1 h / Ambient temperature 4: 78 percent / potassium carbonate / dimethylformamide / 2 h / 140 - 150 °C 5: 86 percent / conc. H2SO4 / H2O; acetic acid / 1.5 h / Heating View Scheme

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: 95 percent / ethanol / 1 h / Ambient temperature 4: 78 percent / potassium carbonate / dimethylformamide / 2 h / 140 - 150 °C View Scheme