Reacción #476078

Ecuación de reacción

Methyl chloroformate

Na2CO3

NaOH

L-valine

→

solid

Rendimiento 102.9%

(S)-2-(Methoxycarbonylamino)-3-methylbutanoic acid

Rendimiento 102.9%

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturathe resulting solution was cooled with ice-water bath
2. 2
   Otrothe cooling bath was removed
3. 3
   LavadoThe reaction mixture was washed with ether (50 mL, 3×)
4. 4
   Temperaturathe aqueous phase was cooled with ice-water bath
5. 5
   Extracciónextracted with CH2Cl2 (50 mL, 3×)
6. 6
   SecadoThe organic phase was dried (MgSO4)
7. 7
   Otroevaporated in vacuo

Procedimiento

Na2CO3 (1.83 g, 17.2 mmol) was added to NaOH (33 mL of 1M/H2O, 33 mmol) solution of L-valine (3.9 g, 33.29 mmol) and the resulting solution was cooled with ice-water bath. Methyl chloroformate (2.8 mL, 36.1 mmol) was added dropwise over 15 min, the cooling bath was removed and the reaction mixture was stirred at ambient temperature for 3.25 hr. The reaction mixture was washed with ether (50 mL, 3×), and the aqueous phase was cooled with ice-water bath and acidified with concentrated HCl to a pH region of 1-2, and extracted with CH2Cl2 (50 mL, 3×). The organic phase was dried (MgSO4) and evaporated in vacuo to afford Cap-51 as a white solid (6 g). 1H NMR for the dominant rotamer (DMSO-d6, δ=2.5 ppm, 500 MHz): 12.54 (s, 1H), 7.33 (d, J=8.6, 1H), 3.84 (dd, J=8.4, 6.0, 1H), 3.54 (s, 3H), 2.03 (m, 1H), 0.87 (m, 6H). HRMS: Anal. Calcd. for [M+H]+ C2H14NO4: 176.0923. found 176.0922.

Fuente