反应详情

温度

0 °C

Sodium hydroxide (0.513 Kg; 12.82 moles) and potassium carbonate (1.77 Kg, 12.82 moles) were dissolved in water (7.5 L) and cooled to 0° C. The resulting solution was treated with (S)-2-aminopentanoic acid (L-norvaline, 0.75 Kg; 6.41 moles) slowly at between 0-5° C. The stirred suspension was heated at 90° C. and benzyl bromide (4.385 Kg, 25.64 moles) was added dropwise. Heating was continued for a further 12 hours at 90° C. The reaction mixture was then cooled to ambient temperature, and extracted with ethyl acetate (2×6 liters). The layers were separated and the aqueous phase extracted twice with ethyl acetate. The combined organic extracts were dried over sodium sulfate, and the solvent removed under reduced pressure to obtain 3.3 Kg of crude (S)-benzyl 2-(dibenzylamino)pentanoate, a compound of formula (3), as a brown oil. This material was used in the next reaction without further purification.

1. temperatureThe stirred suspension was heated at 90° C.
2. temperatureHeating
3. temperatureThe reaction mixture was then cooled to ambient temperature
4. extractionextracted with ethyl acetate (2×6 liters)
5. customThe layers were separated
6. extractionthe aqueous phase extracted twice with ethyl acetate
7. dry with materialThe combined organic extracts were dried over sodium sulfate
8. customthe solvent removed under reduced pressure