1.1: 80 percent / para-toluenesulfonic acid / CH2Cl2; methanol / 0.5 h / cooling 2.1: ammonia sulfate / various solvent(s) / 2 h / 80 °C 2.2: 70 percent / K2CO3 / methanol / 0.5 h / cooling View Scheme

toluene-4-sulfonic acid in methanol; dichloromethane T=0 - 5°C; 0.5 h;