1: 99.8 percent / 4-dimethylaminopyridine / ethyl acetate / 3 h / Ambient temperature 2: dimethylsulfoxide / a) 97 deg C, 2.5 mmHg, b) from 130 deg C to 132 deg C, 9.5 h 3: 75.9 g / NaOH / ethane-1,2-diol / 2.5 h / 180 - 185 °C View Scheme