反应详情

Sodium metal (1.40 g, 61 mmol) was dissolved in EtOH (100 mL) containing diethyl acetamidomalonate (6.62 g, 30.5 mmol) and 3-picolyl chloride hydrochloride (5.00 g, 30.5 mmol) were added. The mixture was heated to reflux for 6 hr, and then cooled and filtered to remove NaCl (washed with EtOH). The solvent was removed in vacuo and the mixture was taken up into saturated aqueous NaHCO3 (100 mL) and extracted with EtOAc (3×100 mL). The solvent was removed and the residue purified by silica gel flash chromatography (95:5 CH2Cl2/MeOH) to give diethyl 2-(3-pyridylmethyl)-2-acetamidomalonate (2.84 g, 30%). Diethyl 2-(3-pyridylmethyl)-2-acetamidomalonate was dissolved in 6N HCl (30 mL) and heated to reflux for 19 hr whereupon it was cooled to room temperature and the HCl solution was removed by evaporation in vacuo. The intermediate amino acid dihydrochloride salt was taken up into MeOH (30 mL) saturated with HCl gas and stirred for 3.5 hr. The MeOH/HCl was removed by evaporation in vacuo to give β-(3-pyridyl)alanine methyl ester dihydrochloride (2.235 g, 100%).

1. additionwere added
2. temperatureThe mixture was heated
3. temperatureto reflux for 6 hr
4. temperaturecooled
5. filtrationfiltered
6. customto remove NaCl (washed with EtOH)
7. customThe solvent was removed in vacuo
8. extractionextracted with EtOAc (3×100 mL)
9. customThe solvent was removed
10. customthe residue purified by silica gel flash chromatography (95:5 CH2Cl2/MeOH)