反应详情

Pivaloyl chloride (4 mL, 38.4 mmol) was added slowly (caution—exothermic reaction) to an ice cold solution of the crude 4-bromo-2-fluoro-6-methylaniline from step 4 (about 32 mmol) in pyridine (20 mL). After the addition, the ice bath was removed and the warm reaction mixture was stirred at room temperature for 30 minutes. The reaction mixture was poured into a water solution of 1 N HCl and extracted with EtOAc. The organic layer was washed with 1N HCl three times, dried over MgSO4, filtered, and concentrated under vacuum. The residue was purified by flash chromatography on a Biotage 40M KP-Sil column, eluting with 9:1 hexanes-EtOAc. The product containing fractions were evaporated under vacuum to provide N-(4-bromo-2-fluoro-6-methylphenyl)-2,2-dimethylpropanamide (4.3 g, 49% for 3 steps) as a yellow solid.

1. additionAfter the addition
2. customthe ice bath was removed
3. customthe warm reaction mixture
4. extractionextracted with EtOAc
5. washThe organic layer was washed with 1N HCl three times
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated under vacuum
9. customThe residue was purified by flash chromatography on a Biotage 40M KP-Sil column
10. washeluting with 9:1 hexanes-EtOAc
11. additionThe product containing fractions
12. customwere evaporated under vacuum