反应详情

To a solution of 3,4-dimethoxybenzenamine (20.0 g, 0.130 mol) in dry THF (200 mL) was added concentrated H2SO4 (20 drops) under N2 at −78° C. After 10 mains, NBS (23.2 g, 0.130 mol) was added in potions at −78° C. Then the reaction mixture was allowed to gradually warm up to room temperature over 1 hour. THF was removed under reduced pressure. The residue was diluted with EtOAc (200 mL), and washed with water (80 mL×3). The organic layer was dried over anhydrous MgSO4, filtered and concentrated in vacuum. The residue was purified by silica gel column (15:1 hexanes/ethyl acetate) to afford 2-bromo-4,5-dimethoxyaniline as a yellow solid. MS (M+H)=232 and 234.

1. customTHF was removed under reduced pressure
2. additionThe residue was diluted with EtOAc (200 mL)
3. washwashed with water (80 mL×3)
4. dry with materialThe organic layer was dried over anhydrous MgSO4
5. filtrationfiltered
6. concentrationconcentrated in vacuum
7. customThe residue was purified by silica gel column (15:1 hexanes/ethyl acetate)