反应详情

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.

1. customprepared analogously to a method of Shimohigashi Y
2. customThe resulting reaction mixture
3. customThe dicyclohexylurea that has precipitated
4. filtrationis filtered off with suction
5. additionthe filtrate is diluted with methylene chloride
6. washwashed with water and phosphate buffer solution
7. dry with materialThe organic phase is dried over sodium sulphate
8. concentrationconcentrated by evaporation
9. customthe oily residue is chromatographed over silica gel