反应详情

4.13 g (20 mmol) of dicyclohexyl carbodiimide and 2.79 ml (20 mmol) of triethylamine are added at room temperature while stirring to a mixture of 3.38 g (20 mmol) of 2-(S)-bromo-3-hydroxypropionic acid and 5.151 g (20 mmol) of p-methoxybenzyl-tert.-butylthiomethylammonium chloride (Example 24) in 100 ml of tetrahydrofuran. The mixture is stirred for two hours at room temperature and the dicyclohexylurea that has precipitated is filtered off with suction. The filtrate is concentrated by evaporation under reduced pressure and the residue is chromatographed over 500 g of silica gel using toluene/ethyl acetate (9:1). The title compound is obtained in the form of a colourless, viscous oil.

1. customthe dicyclohexylurea that has precipitated
2. filtrationis filtered off with suction
3. concentrationThe filtrate is concentrated by evaporation under reduced pressure
4. customthe residue is chromatographed over 500 g of silica gel