1: conc. H2SO4 / acetone; dimethylformamide / 0.5 h 2: 91 percent / pyridine / 4 h / Ambient temperature 3: 82 percent / LiN3 / dimethylformamide / 5 h / 100 °C 4: 94 percent / Dowex 50(H+), 80percent aq. MeOH / 0.67 h / Heating 5: 1) Dowex 1(IO4-), 2) Dowex 1(BH4-) / 1) 80percent aq. MeOH, r.t., 1.5 h, 2) r.t., 1.5 h View Scheme

1: conc. H2SO4 / acetone; dimethylformamide / 0.5 h 2: 91 percent / pyridine / 4 h / Ambient temperature 3: 82 percent / LiN3 / dimethylformamide / 5 h / 100 °C 4: 94 percent / Dowex 50(H+), 80percent aq. MeOH / 0.67 h / Heating View Scheme