Nitric Acid → 6-Bromo-2-nitropyridin-3-ol

HRID 1945601Notes

Reaction equation

HRID 1945601 reaction equation
[Br:1][C:2]1[N:7]=[CH:6][C:5]([OH:8])=[CH:4][CH:3]=1.[N+:9]([O-])([OH:11])=[O:10].[OH-]>C(O)(=O)C.O>[Br:1][C:2]1[N:7]=[C:6]([N+:9]([O-:11])=[O:10])[C:5]([OH:8])=[CH:4][CH:3]=1

Participants

6

Reactant 3

HCID 944Nitric AcidHCID 961HydroxideHCID 27628652-Bromo-5-hydroxypyridine

Product 1

HCID 218738086-Bromo-2-nitropyridin-3-olYield 71%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent

Procedure

To a suspension of 6-bromopyridin-3-ol (2.5 g, 14.4 mmol) in acetic acid (20 mL) at 0° C. was added fuming nitric acid (0.9 mL, 22.4 mmol). The reaction mixture was stirred at room temperature for 1 hour and then at 60° C. for 1 hour. The reaction mixture was cooled to 0° C. and 10M aqueous hydroxide was added dropwise until pH 4-5 (ca 25 mL). The resulting mixture was diluted with water and partially concentrated under reduced pressure. The residue was extracted twice with EtOAc. The organic fractions were combined and washed with water and brine, dried over Na2SO4, filtered and concentrated. The residue was azeotroped with toluene to give 6-Bromo-2-nitropyridin-3-ol as an orange solid (2.2 g, 71%). 1H NMR (400 MHz, DMSO-d6): δ 11.92 (s, 1 H); 7.86-7.83 (d, J=8.6 Hz, 1 H); 7.61 (d, J=8.6 Hz, 1 H).

Workup

  1. waitat 60° C. for 1 hour
  2. temperatureThe reaction mixture was cooled to 0° C.
  3. concentrationpartially concentrated under reduced pressure
  4. extractionThe residue was extracted twice with EtOAc
  5. washwashed with water and brine
  6. dry with materialdried over Na2SO4
  7. filtrationfiltered
  8. concentrationconcentrated
  9. customThe residue was azeotroped with toluene

Sources & evidence

ORD record
ord-1f1c1a9227ef4bf7a683a90f8afc4988
Source dataset
uspto-grants-2013_03
Patent number
US08394796B2

Reaction notes

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