Ethyl Acetate → 7-Bromo-2-ethyl-3-nitropyrazolo[1,5-a]pyridine

HRID 347827

Reaction equation

HRID 347827 reaction equation
[Br:1][C:2]1[N:7]2[N:8]=[C:9]([CH2:11][CH3:12])[CH:10]=[C:6]2[CH:5]=[CH:4][CH:3]=1.F[B-](F)(F)F.[O:18]=[N+:19]=[O:20].C(OCC)(=O)C>C(#N)C>[Br:1][C:2]1[N:7]2[N:8]=[C:9]([CH2:11][CH3:12])[C:10]([N+:19]([O-:20])=[O:18])=[C:6]2[CH:5]=[CH:4][CH:3]=1

Participants

5

Reactant 3

HCID 8857Ethyl AcetateHCID 11073463Nitronium tetrafluoroborateHCID 219845107-Bromo-2-ethylpyrazolo[1,5-a]pyridine

Product 1

HCID 219844817-Bromo-2-ethyl-3-nitropyrazolo[1,5-a]pyridineYield 50.8%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

To a solution of 7-bromo-2-ethylpyrazolo[1,5-a]pyridine (1.1 g) dissolved in acetonitrile (20 mL) was added nitronium tetrafluoroborate (1.3 g) was added thereto while cooling with ice, and the reaction mixture was stirred for 30 minutes. The reaction mixture was then added to ice water, extraction was performed with ethyl acetate, and the organic extract was washed with water and brine. The obtained organic extract was dried over anhydrous magnesium sulfate and filtered, and the solvent was evaporated under reduced pressure. The obtained residue was purified by silica gel column chromatography and the title compound (670 mg) was obtained as yellow crystals from the n-hexane:ethyl acetate (10:1) fraction.

Workup

  1. additionwas added
  2. temperaturewhile cooling with ice
  3. extractionthe organic extract
  4. washwas washed with water and brine
  5. extractionThe obtained organic extract
  6. dry with materialwas dried over anhydrous magnesium sulfate
  7. filtrationfiltered
  8. customthe solvent was evaporated under reduced pressure
  9. customThe obtained residue was purified by silica gel column chromatography

Sources & evidence

ORD record
ord-28ff211ff1784c47abb30078df0ce105
Source dataset
uspto-grants-2007_02
Patent number
US07176216B2

Linked notes

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