反应详情

温度

85 °C

Methyl (2S)-2-(isopropylamino)butanoate 43a (10.75 g, 67.50 mmol) was dissolved in 180 mL of cyclohexane followed by the addition of sodium bicarbonate (22.68 g, 0.27 mol) and 2,4-dichloro-5-nitro-pyrimidine (15.71 g, 0.081 mol) successively, the reaction mixture was heated to 85° C. and stirred for 2.5 hours. The resulting mixture was cooled down to room temperature, added with 200 mL of dichloromethane, then dried over anhydrous magnesium sulfate, filtered and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography with elution system B to obtain methyl (2S)-2-[(2-chloro-5-nitro-pyrimidin-4-yl)-isopropyl-amino]butanoate 43b (8.78 g, yield: 41.1%) as a yellow solid.

1. temperatureThe resulting mixture was cooled down to room temperature
2. dry with materialdried over anhydrous magnesium sulfate
3. filtrationfiltered
4. concentrationthe filtrate was concentrated under reduced pressure
5. customThe resulting residue was purified by silica gel column chromatography with elution system B