1: 93 percent / 20percent aq. KOH / methanol / 1 h / Heating 2: 97 percent / anhydrous HF / 16 h / Ambient temperature 3: 90 percent / hydrazine monohydrate, KOH / bis-(2-hydroxy-ethyl) ether / 6 h / Heating 4: 70 percent / DDQ / toluene / 16 h / Heating View Scheme

1: 93 percent / 20percent aq. KOH / methanol / 1 h / Heating 2: 97 percent / anhydrous HF / 16 h / Ambient temperature 3: 90 percent / hydrazine monohydrate, KOH / bis-(2-hydroxy-ethyl) ether / 6 h / Heating 4: 70 percent / DDQ / toluene / 16 h / Heating 5: 100 percent / H2 / PtO2 / ethyl acetate / 0.17 h View Scheme