反应详情

2-(4-Bromophenyl)acetic acid (20 g, 93 mmol), tert-butyl carbazate (14.7 g, 111 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (21.4 g, 112 mmol) and 1-hydroxybenzotriazole monohydrate (17.1 g, 112 mmol) were dissolved in dichloromethane (400 ml), and N,N-diisopropylethylamine (80 ml) was added. After stirring at room temperature for 16 hrs, the reaction mixture was washed with 1M hydrochloric acid and saturated aqueous sodium hydrogen carbonate solution, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The concentration residue was purified by silica gel column chromatography (dichloromethane:methanol=99:1→90:10) to give tert-butyl 2-[(4-bromophenyl)acetyl]hydrazinecarboxylate (27 g, yield 88%) as a white solid.

1. washthe reaction mixture was washed with 1M hydrochloric acid and saturated aqueous sodium hydrogen carbonate solution
2. dry with materialdried over anhydrous magnesium sulfate
3. concentrationconcentrated under reduced pressure
4. customThe concentration residue was purified by silica gel column chromatography (dichloromethane:methanol=99:1→90:10)