反应详情

Thionyl chloride (12.3 mL, 169 mmol) was added dropwise to methanol (250 mL) at 0° C. followed by addition of 2-amino-3-hydroxy-3-(4-methoxyphenyl)propanoic acid (25.0 g, 118 mol). The reaction mixture was stirred at ambient temperature for 1 h and heated under reflux for 3 h. The mixture was cooled to ambient temperature and then concentrated to dryness. The residue was purified by flash column chromatography on silica gel (DCM/methanol=60:1) to afford (2S,3R)-methyl 2-amino-3-hydroxy-3-(4-methoxyphenyl)propanoate (15.7 g, 59% yield, threo-) as a colorless oil. Further separation by chiral preparative HPLC afforded (2S,3R)-methyl 2-amino-3-hydroxy-3-(4-methoxyphenyl)propanoate (7.0 g, 45% yield).

1. temperatureheated
2. temperatureunder reflux for 3 h
3. temperatureThe mixture was cooled to ambient temperature
4. concentrationconcentrated to dryness
5. customThe residue was purified by flash column chromatography on silica gel (DCM/methanol=60:1)