Triethylamine → N-p-methoxybenzyl-N-tert.-butylthiomethyl-2-(S)-bromo-3-(R)-hydroxybutyramide

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Reaction Steps

In succession, 2.76 g (10 mmol) of p-methoxybenzyl-tert.-butylthiomethylammonium chloride (Example 24), 2.06 g (10 mmol) of dicyclohexyl carbodiimide and, dropwise, 1.40 ml (10 mmol) of triethylamine are added at room temperature to a solution of 1.83 g (10 mmol) of 2-(S)-bromo-3-(R)-hydroxybutyric acid prepared analogously to a method of Shimohigashi Y. et al., Bull. Chem. Soc. Japan 52, 949 (1979). The resulting reaction mixture is stirred at room temperature for 2 hours. The dicyclohexylurea that has precipitated is filtered off with suction and the filtrate is diluted with methylene chloride and washed with water and phosphate buffer solution having a pH of 8. The organic phase is dried over sodium sulphate and concentrated by evaporation and the oily residue is chromatographed over silica gel using toluene/ethyl acetate. The title compound is obtained in the form of a colourless, viscous oil.

Provenance & Evidence