反应详情

To a solution of 3-fluoro-4-(pyrazol-1-yl)phenylamine (2.56 g, 14.5 mmol) in tetrahydrofuran (50 ml) was added dropwise a solution of pyridinium tribromide (5.09 g, 15.9 mmol) in tetrahydrofuran (50 ml). The mixture was stirred for 1 h at room temperature then diluted with ether (250 ml). After stirring for a further 30 min the precipitate was filtered and washed with ether (50 ml×2). The white solid was dissolved in water (200 ml) and extracted with ethyl acetate (100 ml×3). The combined organic phases were dried over magnesium sulphate, filtered and the solvent removed to leave an orange oil. Purification by chromatography on silica gel eluting with dichloromethane gave 2-bromo-5-fluoro-4-(pyrazol-1-yl)phenylamine as a white solid: m/z (ES+) 256 and 258 (M++H).

1. stirringAfter stirring for a further 30 min the precipitate
2. filtrationwas filtered
3. washwashed with ether (50 ml×2)
4. dissolutionThe white solid was dissolved in water (200 ml)
5. extractionextracted with ethyl acetate (100 ml×3)
6. dry with materialThe combined organic phases were dried over magnesium sulphate
7. filtrationfiltered
8. customthe solvent removed
9. customto leave an orange oil
10. customPurification by chromatography on silica gel eluting with dichloromethane