Triethylamine → (2R,3S)-3-hydroxy-2-({[2-(4-methylphenyl)ethoxy]carbonyl}amino) butanoic acid

In a four necked round bottom flask, CDI (9.32 g, 57.4 mmol) was added to a solution of 4-methylphenethyl alcohol (4 mL, 28.7 mmol) in anhydrous DMF (60 mL) under argon. After stirring 2 h at rt, D-threonine (3.42 g, 28.7 mmol) dissolved in water (60 mL) and Et3N (6 mL, 43.1 mmol) were added. The mixture was heated at 50° C. for 16 h, then allowed to cool. Water (600 mL) was added and the mixture washed with Et2O (2×300 mL). The aqueous phase was acidified with 2M HCl solution then extracted with AcOEt (3×500 mL). The collected organic phases were washed with brine and then dried over Na2SO4, filtered and the solvent removed under vacuum. The crude was further co-evaporated with toluene, to yield a pale yellow oil (3.72 g, 46%), which was used in the next step without further purification. Rf=0.4 (Cy/AcOEt 2:8+1% CH3COOH). FTIR (cm−1): 3419(br), 2977, 2932, 1716, 1661, 1517, 1388, 1255, 1226, 1099, 1077, 665.

1. temperatureThe mixture was heated at 50° C. for 16 h
2. temperatureto cool
3. washthe mixture washed with Et2O (2×300 mL)
4. extractionthen extracted with AcOEt (3×500 mL)
5. washThe collected organic phases were washed with brine
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. customthe solvent removed under vacuum

ORD record

ord-7caf7b423c1f42f09b92f647bb91acc6

Source dataset

uspto-grants-2016_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09353075B2