1: 73 percent / silica gel / tetrahydrofuran; H2O / 5 h / 25 °C 2: 22 percent / hydrazine hydrate, KOH / bis-(2-hydroxy-ethyl) ether / 3 h / Heating 3: 92 percent / 5percent aq. HCl / tetrahydrofuran / 1 h / Ambient temperature View Scheme

1: 73 percent / silica gel / tetrahydrofuran; H2O / 5 h / 25 °C 2: 22 percent / hydrazine hydrate, KOH / bis-(2-hydroxy-ethyl) ether / 3 h / Heating 3: 92 percent / 5percent aq. HCl / tetrahydrofuran / 1 h / Ambient temperature 4: 86 percent / pyridine / 5 h / 0 °C View Scheme