Reacción #93720

Ecuación de reacción

p-methoxybenzyl-tert.-butylthiomethylammonium chloride

N-p-methoxybenzyl-N-tert-butylthiomethylammonium chloride

dicyclohexyl carbodiimide

triethylamine

2-(S)-bromo-3-(R)-hydroxybutyric acid

→

title compound

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

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroprepared analogously to a method of Shimohigashi Y
2. 2
   OtroThe resulting reaction mixture
3. 3
   OtroThe dicyclohexylurea that has precipitated
4. 4
   Filtraciónis filtered off with suction
5. 5
   workup.ADDITIONthe filtrate is diluted with methylene chloride
6. 6
   Lavadowashed with water and phosphate buffer solution
7. 7
   SecadoThe organic phase is dried over sodium sulphate
8. 8
   Concentraciónconcentrated by evaporation
9. 9
   Otrothe oily residue is chromatographed over silica gel

Procedimiento

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.

Fuente