1: NaH, 18-crown-6 / 1,2-dimethoxy-ethane / 4 h / Ambient temperature 2: aq. 15percent NaOH / 20 h / Heating 3: conc. H2SO4 / 4 h / Heating 4: 1.) NaOH, 2.) glucose / 1.) MeOH, reflux, 2.) H2O, suspension of baker's yeast, 28 to 30 deg C, 25 h 5: conc. HCl / methanol; H2O / 1 h / 0 °C View Scheme

1: NaH, 18-crown-6 / 1,2-dimethoxy-ethane / 4 h / Ambient temperature 2: aq. 15percent NaOH / 20 h / Heating View Scheme

1: NaH, 18-crown-6 / 1,2-dimethoxy-ethane / 4 h / Ambient temperature 2: aq. 15percent NaOH / 20 h / Heating 3: conc. H2SO4 / 4 h / Heating 4: 1.) NaOH, 2.) glucose / 1.) MeOH, reflux, 2.) H2O, suspension of baker's yeast, 28 to 30 deg C, 25 h View Scheme

1: NaH, 18-crown-6 / 1,2-dimethoxy-ethane / 4 h / Ambient temperature 2: aq. 15percent NaOH / 20 h / Heating 3: conc. H2SO4 / 4 h / Heating View Scheme