Thionyl Chloride → tert.-butyl (4S)-1-methyl-3-[(2S)-3-acetylthio-2-methylpropionyl]-2-oxo-imidazolidine-4-carboxylate

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Reaction Steps

1.3 g of tert.-butyl (4S)-1-methyl-2-oxo-imidazolidine-4-carboxylate are dissolved in 15 ml of tetrahydro-furan, and 0.35 g of sodium hydride (62% oil dispersion) is added thereto under ice-cooling and stirring. A solution of (2S)-3-acetylthio-2-methylpropionyl chloride (prepared by heating a mixture of 1.5 g of (2S)-3-acetylthio-2-methylpropionic acid and 6 ml of thionyl chloride at 50° C. for 3 hours and then evaporting excess thionyl chloride under reduced pressure) in 5 ml of tetrahydrofuran is added dropwise to the mixture. Then, the mixture is treated in the same manner as described in Example 1-(4). 1.0 g of tert.-butyl (4S)-1-methyl-3-[(2S)-3-acetylthio-2-methylpropionyl]-2-oxoimidazolidine-4-carboxylate is obtained as colorless crystals.

Provenance & Evidence