Tin tetrachloride → 6-Amino-5-bromopyridin-3-ol

HRID 2185733Notes

Reaction equation

HRID 2185733 reaction equation
[Br:1][C:2]1[C:3]([N:9]=NC2C=CC([N+]([O-])=O)=CC=2)=[N:4][CH:5]=[C:6]([OH:8])[CH:7]=1.[Sn](Cl)(Cl)(Cl)Cl>Cl.C(O)C>[NH2:9][C:3]1[C:2]([Br:1])=[CH:7][C:6]([OH:8])=[CH:5][N:4]=1

Participants

5

Reactant 2

HCID 24287Tin tetrachlorideHCID 1356101333-Bromo-2-(4-nitrophenylazo)-5-hydroxypyridine

Product 1

HCID 184590446-Amino-5-bromopyridin-3-olYield 34%

Reagents, catalysts & solvents 2

HCID 313Hydrochloric AcidSolventHCID 702EthanolSolvent

Conditions

Temperature
0 °C

Procedure

The compound from 31b above (5.0 g, 15.8 mmol) and tin chloride (25 g, 111 mmol) were suspended in concentrated HCl and ethanol (150 mL), and the mixture was heated at reflux for 1 hour. The mixture was cooled to 0° C., then filtered. The filtrate was neutralized with sodium bicarbonate (180 g) and extracted with ethyl acetate. The organic extracts were washed with brine, dried (MgSO4) and concentrated. The residue was chromatographed (silica gel; chloroform/methanol/NH4OH, 95:5:0.5-90:10:1) to afford the title compound (3.3 g, 34% yield): MS (CI/NH3) m/z 189, 191 (M+H)+; 1H NMR (DMSO-d6, 300 MHz) δ7.57 (d, J=2.6 Hz, 1H), 7.43 (d, J=2.6 Hz, 1H).

Workup

  1. temperatureat reflux for 1 hour
  2. filtrationfiltered
  3. extractionextracted with ethyl acetate
  4. washThe organic extracts were washed with brine
  5. dry with materialdried (MgSO4)
  6. concentrationconcentrated
  7. customThe residue was chromatographed (silica gel; chloroform/methanol/NH4OH, 95:5:0.5-90:10:1)

Sources & evidence

ORD record
ord-6921d500e6084433b88ceda1f1aea263
Source dataset
uspto-grants-2002_06
Patent number
US06403575B1

Reaction notes

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