反应详情

温度

0 °C

(2S)—N-(tert-Butoxycarbonyl)-3-(pyridin-3-yl)alanine (25.00 g, 93.88 mmol) is dissolved in 300 ml of dichloromethane under argon. Methanol (11.4 ml, 9.02 g, 281 mmol, 3 equivalents) and one grain of DMAP are added. The mixture is then cooled to 0° C. EDC (19.80 g, 103 mmol, 1.1 equivalents) is added. After 5 min, the ice bath is removed and the mixture is left to stir at RT over 1 h. The mixture is then concentrated in vacuo, and ethyl acetate is added to the residue and the mixture is extracted against a saturated sodium hydrogen carbonate solution. The aqueous phase is reextracted once with ethyl acetate, then the combined organic phases are washed with 0.5 M citric acid and then once again with a saturated sodium hydrogen carbonate solution. The organic phase is dried over sodium sulfate, filtered and concentrated in vacuo. An oil remains, which crystallizes during drying in an oil-pump vacuum. Yield: 23.60 g (90% of theory).

1. customthe ice bath is removed
2. waitthe mixture is left
3. concentrationThe mixture is then concentrated in vacuo, and ethyl acetate
4. additionis added to the residue
5. extractionthe mixture is extracted against a saturated sodium hydrogen carbonate solution
6. washthe combined organic phases are washed with 0.5 M citric acid
7. dry with materialThe organic phase is dried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated in vacuo
10. customwhich crystallizes
11. customduring drying in an oil-pump vacuum