1: 97 percent / K2CO3 / dimethylformamide / 1 h / 80 - 100 °C 2: 2.) PPE / 1.) 130-135 deg C, 2h; 2.) 140-145 deg C, 1.5h 3: 75 percent / conc. HCl / acetic acid / 4 h / 100 - 110 °C 4: 41 percent / dimethylsulfoxide / 6 h / 100 - 140 °C View Scheme