Reaction #84041

Reaction equation

Methyl chloroformate

NaOH

L-Threonine

sodium carbonate

→

foam

(2S,3R)-3-hydroxy-2-(methoxycarbonylamino)butanoic acid

Conditions

Workup

1. 1
   Otherreach room temperature
2. 2
   WashThe reaction mixture is washed with CH2Cl2 (3×50 mL)
3. 3
   Otherthe aqueous layer is contained in a round bottom flask
4. 4
   Temperaturecooled over an ice-water bath
5. 5
   workup.ADDITIONConcentrated HCl (aq) is added drop wise until pH 2
6. 6
   Otheris brought to room temperature
7. 7
   Otherthe water is removed in vacuum
8. 8
   workup.ADDITIONThe residue was taken up in a 2:1 mixture of MeOH/CH2Cl2 (150 mL
9. 9
   Filtrationfiltered
10. 10
    Washwashed with 2:1 mixture of MeOH/CH2Cl2 (50 mL)
11. 11
    ConcentrationThe filtrate was concentrated
12. 12
    Otherdried in vacuum at 40° C.

Procedure

An aqueous NaOH (1 M, 167 mL) solution is added, while stirring, to L-Threonine (20 g, 30.5 mmol) in a round bottom flask (1 L). To this solution was added sodium carbonate (9.8 g, 92.3 mmol). The flask is cooled to 0° C. in an ice-water bath. Methyl chloroformate (14.3 mL, 184.7 mmol) is added drop wise and the reaction mixture is allowed to stir for 15 hours and reach room temperature. The reaction mixture is washed with CH2Cl2 (3×50 mL), and the aqueous layer is contained in a round bottom flask and cooled over an ice-water bath. Concentrated HCl (aq) is added drop wise until pH 2. The aqueous solution is brought to room temperature and the water is removed in vacuum. The residue was taken up in a 2:1 mixture of MeOH/CH2Cl2 (150 mL, filtered and washed with 2:1 mixture of MeOH/CH2Cl2 (50 mL). The filtrate was concentrated and dried in vacuum at 40° C., resulting in white foam (29.1 g, 98%).

Source