反应详情

A solution of 2.30 g of N-acetylphenylalanine methyl ester (10.40 mmol) in 15 ml of tetrahydrofuran is chilled at -60° C. with dry ice/acetone bath. To the mixture is added dropwise 10.40 ml of 2M solution of isopropylmagnesium chloride in tetrahydrofuran (20.8 mmol) with stirring and the mixture allowed to stand for 15 minutes and returned to room temperature. The mixture was stirred for 3 hours. To the mixture is added saturated aqueous ammonium chloride under ice cooling, followed by the addition of 5% hydrochloric acid and the mixture extracted with ethyl acetate. The extract is washed with saturated brine, dried over sodium sulfate, filtered and the filtrate concentrated in vacuo. The resulting crude product is chromatographed on a column of silica gel, eluting with methylene chloride and ethyl acetate (4:1) to give 1.40 g of the objective 4-acetylamino-2-methyl-5-phenyl-3-pentanone 5. Yield, 57.7%.

1. customreturned to room temperature
2. stirringThe mixture was stirred for 3 hours
3. extractionthe mixture extracted with ethyl acetate
4. washThe extract is washed with saturated brine
5. dry with materialdried over sodium sulfate
6. filtrationfiltered
7. concentrationthe filtrate concentrated in vacuo
8. customThe resulting crude product is chromatographed on a column of silica gel
9. washeluting with methylene chloride and ethyl acetate (4:1)