反応 #159228

反応方程式

water

MeI

2-tert-Butoxycarbonylamino-3-hydroxy-3-methyl-butyric acid

NaH

→

2-tert-Butoxycarbonylamino-3-methoxy-3-methyl-butyric acid

収率 94.0%

溶媒

ethyl acetate

THF

反応条件

後処理

1. 1
   workup.ADDITIONUpon completion of the addition
2. 2
   その他the solution was removed from the ice bath
3. 3
   温度to warm to room temperature
4. 4
   その他the crude reaction mixture
5. 5
   workup.STIRRINGwith stirring
6. 6
   濃縮The quenched mixture was concentrated in vacuo
7. 7
   その他partitioned between diethyl ether and water
8. 8
   抽出The ether layer was extracted with sodium bicarbonate twice
9. 9
   抽出extracted three times with ethyl acetate
10. 10
    洗浄The combined ethyl acetate layers were washed with water, sodium thiosulfate, water
11. 11
    乾燥dried with sodium sulfate
12. 12
    濃縮concentrated

実験手順

2-tert-Butoxycarbonylamino-3-hydroxy-3-methyl-butyric acid (1.0 g, 4.29 mmol) was dissolved in THF (14 mL) and cooled to 0° C. in an external ice/brine bath. MeI (2.13 mL, 34.3 mmol) was added at 0° C. Solid NaH (60% dispersion in mineral oil, 0.514 g, 12.87 mmol) was added slowly at 0° C. Upon completion of the addition, the solution was removed from the ice bath and allowed to warm to room temperature, and stirred. After 18 hours, the crude reaction mixture was diluted in ethyl acetate and water was added slowly with stirring. The quenched mixture was concentrated in vacuo and partitioned between diethyl ether and water. The ether layer was extracted with sodium bicarbonate twice. The combined bicarbonate layers were acidified with aqueous citric acid to pH 3 and extracted three times with ethyl acetate. The combined ethyl acetate layers were washed with water, sodium thiosulfate, water, dried with sodium sulfate and concentrated to yield 2-tert-Butoxycarbonylamino-3-methoxy-3-methyl-butyric acid (0.99 g, 94%) as an oil.

出典