1: 82 percent / p-toluenesulfonic acid / dioxane / 2 h / 23 °C 2: 78 percent / NaOH / acetonitrile; methanol; H2O 3: pyridine, (N,N-dimethylamino)pyrydine / CH2Cl2 / 1 h / 5 °C 4: tertbutylammonium fluoride / tetrahydrofuran / 5 h / 5 °C 5: 41 percent / Dowex 50W x 2-100 / methanol / 1 h / 23 °C 6: 80 percent / sat. NH3 in MeOH / 16 h / 20 °C View Scheme