1: 97 percent / conc. H2SO4, CrO3 / 0.25 h / 0 °C 2: 37 percent / diethyl ether / 0.5 h / 0 °C 3: 69 percent / 85percent aq. hydrazine hydrate / 10percent Pd-C / ethanol / 4 h / Heating 4: 55 percent / 2 h / 160 °C View Scheme

1: 97 percent / conc. H2SO4, CrO3 / 0.25 h / 0 °C 2: 37 percent / diethyl ether / 0.5 h / 0 °C 3: 69 percent / 85percent aq. hydrazine hydrate / 10percent Pd-C / ethanol / 4 h / Heating 4: 62 percent / 185 °C View Scheme