反应详情

温度

-30 °C

9.38 g of 2-methoxyphenylacetic acid are added at room temperature to a suspension of 1.89 g of sodium hydride (80% dispersion in petroleum jelly) in 200 cm3 of dry tetrahydrofuran. This suspension is cooled to −30° C., 7.77 cm3 of pivaloyl chloride are added and then a solution, cooled to −78° C., obtained by adding a solution of 35.27 cm3 of 1.6M butyllithium in hexane to a solution, cooled to −78° C., of 10 g of (4S,5S)-4-methyl-5-phenyloxazolidin-2-one in 200 cm3 of dry tetrahydrofuran is finally added. The reaction mixture is stirred for 45 minutes at −30° C. and then, after returning to room temperature, 200 cm3 of a saturated aqueous ammonium chloride solution and then 500 cm3 of ethyl acetate are added; after separating by settling, the organic phase is washed twice with 100 cm3 of water and then twice with 100 cm3 of a saturated aqueous sodium chloride solution, dried over magnesium sulphate and concentrated to dryness under reduced pressure (2.7 kPa). The residue is chromatographed on a column of silica gel (particle size 0.04-0.06 mm, diameter 4.8 cm, height 36 cm), eluting under a pressure of 0.6 bar of nitrogen with a mixture of cyclohexane and ethyl acetate (85/15 and then 80/20 by volume) and collecting 50 cm3 fractions. Fractions 14 to 31 are combined and concentrated to dryness under reduced pressure (2.7 kPa). There are obtained 13.6 g of (4S,5S)-4-methyl-5-phenyl-3-(2-methoxyphenylacetyl)oxazolidin-2-one in the form of a yellow oil.

1. temperaturea solution, cooled to −78° C.
2. customobtained
3. additionis finally added
4. customafter returning to room temperature
5. customafter separating
6. washthe organic phase is washed twice with 100 cm3 of water
7. dry with materialtwice with 100 cm3 of a saturated aqueous sodium chloride solution, dried over magnesium sulphate
8. concentrationconcentrated to dryness under reduced pressure (2.7 kPa)
9. customThe residue is chromatographed on a column of silica gel (particle size 0.04-0.06 mm, diameter 4.8 cm, height 36 cm)
10. washeluting under a pressure of 0.6 bar of nitrogen with a mixture of cyclohexane and ethyl acetate (85/15
11. custom80/20 by volume) and collecting 50 cm3 fractions
12. concentrationconcentrated to dryness under reduced pressure (2.7 kPa)