1: 92 percent / sulfuric acid / 4 h / Heating 2: 91 percent / ammonia / ethanol / 48 h / 120 °C 3: 90 percent / anh. potassium carbonate / acetone / 15 h / Heating 4: 91 percent / pyridine, trifluoroacetic anhydride / CH2Cl2 / Ambient temperature View Scheme

1: 92 percent / sulfuric acid / 4 h / Heating 2: 70 percent / p-toluenesulfonic acid monohydrate / toluene / 9 h / Heating 3: 81 percent / hydrogen / 10percent Pd/C / acetic acid / 12 h / 2844.3 Torr / Ambient temperature 4: 88 percent / phosphoryl chloride / 1 h / 120 °C 5: 80 percent / sodium methoxide / methanol / 5 h / Heating 6: 50 percent / lithium aluminum hydride / tetrahydrofuran / 22 h / 0 °C View Scheme