1: 83 percent / triethylamine / ethanol / 5 h / Heating 2: 57 percent / PPA / 0.5 h / 130 °C 3: 66 percent / PPA / 0.5 h / 150 °C 4: 68 percent / POCl3 / 1 h / Heating 5: 89 percent / triethylamine; H2 / Pd/C / methanol / 20 °C View Scheme