反应详情

Dicyclohexylcarbodiimide (4.14 g) was added to a stirred solution of 6-amino-3-bromo-2-hydroxybenzoic acid (Intermediate 63, 3.88 g) and DMAP (0.102 g) in tert-butanol (20 mL) and THF (150 mL). The mixture was stirred at room temperature for 4 hours. The resultant white precipitate was filtered off and washed with ethyl acetate. The filtrate was concentrated in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane, with a gradient of 2.5-15% to give tert-butyl 6-amino-3-bromo-2-hydroxybenzoate (1.16 g) as a yellow solid.

1. filtrationThe resultant white precipitate was filtered off
2. washwashed with ethyl acetate
3. concentrationThe filtrate was concentrated in vacuo
4. customthe residue was purified by chromatography on silica
5. washeluting with a mixture of ethyl acetate and cyclohexane, with a gradient of 2.5-15%