Sodium Dithionite → Methyl 2-amino-4-bromo-3-hydroxybenzoate

HRID 1505250Notes

Reaction equation

HRID 1505250 reaction equation
[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]

Participants

7

Reactant 2

HCID 24489Sodium DithioniteHCID 58497911Methyl 4-bromo-3-hydroxy-2-nitrobenzoate

Product 1

HCID 58498018Methyl 2-amino-4-bromo-3-hydroxybenzoateYield 88.2%

Reagents, catalysts & solvents 4

HCID 313Hydrochloric AcidSolventHCID 962WaterSolventHCID 8028TetrahydrofuranSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
60 °C

Procedure

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.

Workup

  1. stirringthe mixture vigorously shaken
  2. customThe phases were separated
  3. extractionthe aqueous phase was extracted with ethyl acetate (60 ml)
  4. washThe combined organic extracts were washed with brine
  5. dry with materialdried over sodium sulfate
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-ea755dd5cf44467082b33a581ce9b579
Source dataset
uspto-grants-2015_12
Patent number
US09216973B2

Reaction notes

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