Reacción #159229

Ecuación de reacción

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

HCl

sodium hydroxide

methyl chloroformate

HCl

→

3-Methoxy-2-methoxycarbonylamino-3-methyl-butyric acid

Rendimiento 65.0%

Disolventes

dioxane

Condiciones de reacción

Tratamiento posterior

1. 1
   Concentraciónthe concentrated to dryness
2. 2
   workup.DISSOLUTIONThe solid was dissolved in THF (14 mL)
3. 3
   Temperaturacooled to 0° C. in an external ice/brine bath
4. 4
   workup.ADDITIONUpon completion of the addition
5. 5
   Otrothe solution was removed from the ice bath
6. 6
   Temperaturato warm to room temperature
7. 7
   workup.STIRRINGstirred
8. 8
   workup.WAITAfter 18 hours
9. 9
   Otrothe crude reaction mixture
10. 10
    Extracciónextracted twice with diethyl ether
11. 11
    LavadoThe combined organic layers were washed with brine
12. 12
    Secadodried with magnesium sulfate
13. 13
    Concentraciónconcentrated

Procedimiento

2-tert-Butoxycarbonylamino-3-methoxy-3-methyl-butyric acid was dissolved in dioxane (40 mL) and HCl (4N in dioxane, 5.4 mL, 21.6 mmol) was added at room temperature. The resulting solution was stirred at room temperature for 18 hours and the concentrated to dryness. The solid was dissolved in THF (14 mL) and cooled to 0° C. in an external ice/brine bath. Aqueous sodium hydroxide (6.25M, 1.9 mL, 11.76 mmol) and methyl chloroformate (0.5 mL, 5.88 mmol) were added 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 adjusted to pH 1 with 1N HCl and extracted twice with diethyl ether. The combined organic layers were washed with brine, dried with magnesium sulfate and concentrated to give 3-Methoxy-2-methoxycarbonylamino-3-methyl-butyric acid (0.653 g, 65%) as an off-white solid.

Fuente