1: carbonic acid dimethyl ester / ethanol 2: potassium tert-butylate / isopropyl alcohol; tert-butyl alcohol 3: methanesulfonic acid / acetone View Scheme

1: triethylamine; carbonic acid dimethyl ester / 0.5 h / 4 - 10 °C / |Large scale 2: potassium tert-butylate / isopropyl alcohol; tert-butyl alcohol / 1 h / 20 °C / |Large scale 3: sodium bis(2-methoxyethoxy)aluminium dihydride / toluene / 0.25 h / 10 °C / |Large scale View Scheme

1: 1.) NaOH / 1.) H2O, 70 deg C; 2.) H2O, 70 deg C, 2.5 h 2: 61 percent / pyridine / 2 h / -10 °C 3: 84 percent / Et3N / CH2Cl2 / 0.5 h / 0 - 5 °C 4: 2N NaOH / dioxane / 4 h / Ambient temperature 5: 32percent NH4OH / methanol / 6 h / sealed flask 6: ethyl acetate / 16 h View Scheme

1: 1.) NaOH / 1.) H2O, 70 deg C; 2.) H2O, 70 deg C, 2.5 h 2: 61 percent / pyridine / 2 h / -10 °C 3: 84 percent / Et3N / CH2Cl2 / 0.5 h / 0 - 5 °C 4: 2N NaOH / dioxane / 4 h / Ambient temperature 5: 32percent NH4OH / methanol / 6 h / sealed flask 6: ethyl acetate / 16 h View Scheme

1: 32percent NH4OH / methanol / 6 h / sealed flask 2: ethyl acetate / 16 h View Scheme

1: 61 percent / pyridine / 2 h / -10 °C 2: 84 percent / Et3N / CH2Cl2 / 0.5 h / 0 - 5 °C 3: 2N NaOH / dioxane / 4 h / Ambient temperature 4: 32percent NH4OH / methanol / 6 h / sealed flask 5: ethyl acetate / 16 h View Scheme

1: MCPBA / CH2Cl2 / 0 deg C, 1.5 h, then RT, 24 h 2: 1.) NaOH / 1.) H2O, 70 deg C; 2.) H2O, 70 deg C, 2.5 h 3: 61 percent / pyridine / 2 h / -10 °C 4: 84 percent / Et3N / CH2Cl2 / 0.5 h / 0 - 5 °C 5: 2N NaOH / dioxane / 4 h / Ambient temperature 6: 32percent NH4OH / methanol / 6 h / sealed flask 7: ethyl acetate / 16 h View Scheme

1: 84 percent / Et3N / CH2Cl2 / 0.5 h / 0 - 5 °C 2: 2N NaOH / dioxane / 4 h / Ambient temperature 3: 32percent NH4OH / methanol / 6 h / sealed flask 4: ethyl acetate / 16 h View Scheme

1: 2N NaOH / dioxane / 4 h / Ambient temperature 2: 32percent NH4OH / methanol / 6 h / sealed flask 3: ethyl acetate / 16 h View Scheme

1: sodium carbonate; acetic acid / dichloromethane; water / 6 h / 15 - 25 °C 2: sodium hydroxide; tri-n-butylmethylammonium chloride / water / 4 h / 60 °C / |Large scale 3: triethylamine / ethyl acetate / 0.42 h / -15 °C 4: triethylamine / ethyl acetate / 0.25 h / -15 °C 5: hydrogenchloride / water; ethyl acetate / 0.5 h / 15 - 25 °C 6: sodium hydroxide; tri-n-butylmethylammonium chloride / water / 2 h / 20 - 25 °C / |Large scale 7: ammonium hydroxide / methanol / 3 h / 40 °C / |Large scale 8: dichloromethane; isopropyl alcohol / 5 h / |Large scale View Scheme