L-Threonine → (Methoxycarbonyl)-L-threonine

Temperature

0 °C

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%).

1. customreach room temperature
2. washThe reaction mixture is washed with CH2Cl2 (3×50 mL)
3. customthe aqueous layer is contained in a round bottom flask
4. temperaturecooled over an ice-water bath
5. additionConcentrated HCl (aq) is added drop wise until pH 2
6. customis brought to room temperature
7. customthe water is removed in vacuum
8. additionThe residue was taken up in a 2:1 mixture of MeOH/CH2Cl2 (150 mL
9. filtrationfiltered
10. washwashed with 2:1 mixture of MeOH/CH2Cl2 (50 mL)
11. concentrationThe filtrate was concentrated
12. customdried in vacuum at 40° C.

ORD record

ord-b91adc4da59b48229468cf730202c0b0

Source dataset

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09433609B2