1: 74 percent / NaBH4 / methanol / 6 h / Ambient temperature 2: 84 percent / pyridine / CH2Cl2 / 20 h / Ambient temperature 3: 1) sulphuryl chloride; 2) triethylamine / 1) CH2Cl2, -40 deg C, 20 min; 2) CH2Cl2, DMF, -40 to 20 deg C 4: conc. HCl / 2-methoxy-ethanol / 4 h / Heating View Scheme

1: 74 percent / NaBH4 / methanol / 6 h / Ambient temperature 2: 84 percent / pyridine / CH2Cl2 / 20 h / Ambient temperature 3: 1) sulphuryl chloride; 2) triethylamine / 1) CH2Cl2, -40 deg C, 20 min; 2) CH2Cl2, DMF, -40 to 20 deg C 4: conc. HCl / 2-methoxy-ethanol / 4 h / Heating View Scheme

1: 74 percent / NaBH4 / methanol / 6 h / Ambient temperature 2: 84 percent / pyridine / CH2Cl2 / 20 h / Ambient temperature 3: 1) sulphuryl chloride; 2) triethylamine / 1) CH2Cl2, -40 deg C, 20 min; 2) CH2Cl2, -40 to 20 deg C 4: conc. HCl / 2-methoxy-ethanol / 4 h / Heating View Scheme