Reacción #167170

Ecuación de reacción

water

MeI

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

NaH

→

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

Rendimiento 94.0%

Disolventes

ethyl acetate

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONUpon completion of the addition
2. 2
   Otrothe solution was removed from the ice bath
3. 3
   Temperaturato warm to room temperature
4. 4
   Otrothe crude reaction mixture
5. 5
   workup.STIRRINGwith stirring
6. 6
   ConcentraciónThe quenched mixture was concentrated in vacuo
7. 7
   Otropartitioned between diethyl ether and water
8. 8
   ExtracciónThe ether layer was extracted with sodium bicarbonate twice
9. 9
   Extracciónextracted three times with ethyl acetate
10. 10
    LavadoThe combined ethyl acetate layers were washed with water, sodium thiosulfate, water
11. 11
    Secadodried with sodium sulfate
12. 12
    Concentraciónconcentrated

Procedimiento

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.

Fuente