1: 93.3 percent / conc. HCl / methanol / 2.5 h / 20 °C 2: pyridinium p-toluene-sulfonate / 2 h / 20 °C 3: Ac2O / 6 h / 120 - 130 °C 4: 93.4 percent / 2 N NaOH / methanol / 1.5 h / 20 °C 5: 34.6 percent / diethyl azodicarboxylate; triphenylphosphine / dioxane / 10 h / 20 °C 6: 82.5 percent / NH3 / methanol / 20 h / 80 - 90 °C 7: 86 percent / aq. CF3CO2H / 3 h / 50 °C View Scheme