sodium hydroxide; magnesium oxide in 1,4-dioxane

1: 1) n-BuLi / 1) THF, -78 deg C, 15 min, 2) THF, -78 to 20 deg C then RT, 48 h 2: n-BuLi / tetrahydrofuran / -40 °C 3: 6percent Na-Hg, Na2HPO4 / methanol / 3 h / 0 - 20 °C 4: PPTS / ethanol / 6 h / 50 °C 5: CrO3, H2SO4 / 1 h / 0 - 20 °C View Scheme

chromium(VI) oxide; sulfuric acid T=0 - 20°C; 1 h; Yield given;

1: 6percent Na-Hg, Na2HPO4 / methanol / 3 h / 0 - 20 °C 2: PPTS / ethanol / 6 h / 50 °C 3: CrO3, H2SO4 / 1 h / 0 - 20 °C View Scheme