1: 11.5 percent / 1 N aq. H2SO4 / dioxane / 0.5 h / Irradiation 2: H2, acetic acid / PtO2 / dioxane / 760 Torr 3: 98 percent / pyridine / 1 h / 70 °C 4: 96.3 percent / H2SO4, conc. aq. HNO3 / 1 h 5: 82.3 percent / 20percent aq. H2SO4 / 2 h / Heating 6: 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) / dioxane / 2 h / Heating 7: 96.2 percent / H2 / PtO2 / ethanol; dioxane / 2 h / 760 Torr View Scheme

sulfuric acid in dioxane-acetonitrile-water

dihydrogen peroxide; acetic acid T=70 - 80°C; 3.5 h;

1: 12 percent / Pb(OAc)4, trifluoroacetic acid / 0.25 h / Ambient temperature 2: 90.6 percent / 30percent aq. H2O2, acetic acid / 3.5 h / 70 - 80 °C View Scheme

pyridine; sulfuric acid; acetic anhydride in 1,4-dioxane; methanol