Phosphorus oxybromide → ethyl 6-bromo-1H-pyrazolo[3,4-b]pyridine-4-carboxylate

HRID 1854008Notes

Reaction equation

HRID 1854008 reaction equation
O[C:2]1[CH:3]=[C:4]([C:11]([O:13][CH2:14][CH3:15])=[O:12])[C:5]2[CH:10]=[N:9][NH:8][C:6]=2[N:7]=1.P(Br)(Br)([Br:18])=O>C(#N)C>[Br:18][C:2]1[CH:3]=[C:4]([C:11]([O:13][CH2:14][CH3:15])=[O:12])[C:5]2[CH:10]=[N:9][NH:8][C:6]=2[N:7]=1

Participants

4

Reactant 2

HCID 24613Phosphorus oxybromideHCID 178469358ethyl 6-oxo-1,2-dihydropyrazolo[3,4-b]pyridine-4-carboxylate

Product 1

HCID 59766670ethyl 6-bromo-1H-pyrazolo[3,4-b]pyridine-4-carboxylateYield 77.1%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent2×

Procedure

Ethyl 6-hydroxy-1H-pyrazolo[3,4-b]pyridine-4-carboxylate (25 g, 120 mmol) was suspended in acetonitrile (250 mL) and POBr3 (69.56 g, 241.54 mmol) was added to it. The reaction mixture was refluxed for 6 h. On completion of reaction, acetonitrile was removed under reduced pressure and residue neutralized with saturated NaHCO3 solution was added to it. Extraction was carried out using ethyl acetate; the combined organic layers were washed with water, brine and dried over anhydrous Na2SO4; filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to provide the desired intermediate (25 g, 77%).

Workup

  1. temperatureThe reaction mixture was refluxed for 6 h
  2. customwas removed under reduced pressure and residue
  3. additionwas added to it
  4. extractionExtraction
  5. washthe combined organic layers were washed with water, brine
  6. dry with materialdried over anhydrous Na2SO4
  7. filtrationfiltered
  8. concentrationconcentrated under reduced pressure
  9. customThe residue was purified by silica gel column chromatography

Sources & evidence

ORD record
ord-503a7a6927b649398b44bf8e6ab1dd69
Source dataset
uspto-grants-2015_02
Patent number
US08962620B2

Reaction notes

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