反应详情

To a solution of 3-bromo-5-nitro-benzoic acid methyl ester (D11) (12.1 g, 46.5 mmol, 1 equiv) in MeOH (200 ml) was added SnCl2 (44 g, 233 mmol, 5 equiv). The resulting mixture was stirred at reflux for 4 h, cooled to room temperature and concentrated in vacuo. The residue was partitioned between ice-cold AcOEt and H2O. The aqueous phase was basified with 2N aqueous NaOH solution until a white precipitate appeared, then slowly with 12.5N aqueous NaOH solution until this precipitate disappeared. The temperature was kept below 10° C. during this addition. The two layers were separated and the aqueous phase extracted with AcOEt. The combined organic layers were washed with brine, dried over MgSO4 and concentrated in vacuo to give 3-amino-5-bromo-benzoic acid methyl ester (D12) (9.9 g, 93%) as a brown solid.

1. temperatureat reflux for 4 h
2. concentrationconcentrated in vacuo
3. customThe residue was partitioned between ice-cold AcOEt and H2O
4. additionThe temperature was kept below 10° C. during this addition
5. customThe two layers were separated
6. extractionthe aqueous phase extracted with AcOEt
7. washThe combined organic layers were washed with brine
8. dry with materialdried over MgSO4
9. concentrationconcentrated in vacuo