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

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Reaction Steps

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.

Provenance & Evidence