反应详情

(S)-2-(t-Butoxycarbonylamino)-3-(biphenyl-4-yl)propionic acid (5 g, 14.6 mmol) is dissolved in methylene chloride (25 mL) under nitrogen and the solution is cooled to 0°. Benzyl alcohol (2 mL, 19 mmol) and 4-dimethylaminopyridine (0.1 g) are added, followed by a solution of dicyclohexyl-carbodiimide (3.3 g, 16.1 mmol) in methylene chloride (15 mL). After stirring for 1 hours at 0° and 1 hours at room temperature, the reaction mixture is filtered and the filtrate concentrated in vacuo. The residue is redissolved in ether (100 mL), washed successively with water, 0.5M sodium dihydrogenophosphate, water, saturated sodium bicarbonate and water. The organic layer is dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. (S)-2-(t-butoxycarbonylamino)-3-(biphenyl-4-yl)-propionic acid benzyl ester is obtained as a white solid, [α]D =-3.33 (c 0.91, CHCl3).

1. temperaturethe solution is cooled to 0°
2. filtrationthe reaction mixture is filtered
3. concentrationthe filtrate concentrated in vacuo
4. dissolutionThe residue is redissolved in ether (100 mL)
5. washwashed successively with water, 0.5M sodium dihydrogenophosphate, water, saturated sodium bicarbonate and water
6. dry with materialThe organic layer is dried over anhydrous sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure