[CH3:1][O:2][C:3](=[O:15])[C:4]1[CH:9]=[CH:8][C:7]([Br:10])=[C:6]([OH:11])[C:5]=1[N+:12]([O-])=O.S(S([O-])=O)([O-])=O.[Na+].[Na+]>O1CCCC1.O.C(OCC)(=O)C.Cl>[CH3:1][O:2][C:3](=[O:15])[C:4]1[CH:9]=[CH:8][C:7]([Br:10])=[C:6]([OH:11])[C:5]=1[NH2:12]To a solution of 4-bromo-3-hydroxy-2-nitro-benzoic acid methyl ester (Example 6.2) (3.13 g) in tetrahydrofuran (40 ml) was added a solution of sodium dithionite (10.23 g) in water (40 ml). The reaction mixture was stirred at 60° C. for 2 hours. Then the reaction was diluted with ethyl acetate (80 ml) and aqueous hydrochloric acid (1M) (30 ml) and the mixture vigorously shaken. The phases were separated and the aqueous phase was extracted with ethyl acetate (60 ml). The combined organic extracts were washed with brine, dried over sodium sulfate and concentrated to give 2-amino-4-bromo-3-hydroxy-benzoic acid methyl ester (2.46 g). 1H-NMR (400 MHz, CDCl3): 7.35 (d, 1H), 6.72 (d, 1H), 6.05 (s, 1H), 5.47 (s, 1H), 3.87 (s, 3H) ppm.
読み込み中…
