Dicyclohexylcarbodiimide → N-allyl-N-phenylthiomethyl-(R)-glycidic acid amide

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Reaction Steps

Analogously to Example 5, 8.45 g (50 mmol) of 2-(S)-bromo-3-hydroxypropionic acid in 200 ml of tetrahydrofuran is converted using 15.2 g (100 mmol) of 1,5-diazabicyclo[5.4.0]undec-5-ene into the DBU salt of (R)-glycidic acid. To the latter there are added in situ in methylene chloride at room temperature, 10.31 g (50 mmol) of dicyclohexyl carbodiimide and then, at 0°, 10.75 g (50 mmol) of N-allyl-N-phenylthiomethylammonium chloride. The resulting mixture is stirred for a further 3 hours at room temperature. The crystalline dicyclohexylurea is filtered off with suction, methylene chloride is added to the filtrate and the whole is washed with phosphate buffer having a pH of 8.0. The crude product obtained from the organic phase by drying over sodium sulphate and concentration by evaporation in vacuo is chromatographed over 500 g of silica gel using toluene/ethyl acetate (9:1) and the pure title compound is obtained in the form of a colourless oil.

Provenance & Evidence