1: 54 percent / xylene / 7 h / 140 - 150 °C 2: 1.) NBS, 2.) DBU / 1.) CCl4, reflux, 1h, 2.) THF, 2h, RT 3: 68 percent / CF3CO3H, Na2HPO4 / CH2Cl2 / 15 h / Ambient temperature 4: 97 percent / Et3N, H2O, MeOH / 2 h / Ambient temperature View Scheme

 in  xylene T=140 - 150°C; 7 h;