N-bromobutanimide → 3-Bromo-pyrazolo[1,5-a]pyridine

HRID 1500755Notes

Reaction equation

HRID 1500755 reaction equation
[Br:1]N1C(=O)CCC1=O.C(=O)([O-])O.[Na+].[N:14]1[N:18]2[CH:19]=[CH:20][CH:21]=[CH:22][C:17]2=[C:16](C(O)=O)[CH:15]=1>O>[Br:1][C:16]1[CH:15]=[N:14][N:18]2[CH:19]=[CH:20][CH:21]=[CH:22][C:17]=12

Participants

5

Reactant 3

HCID 67184N-bromobutanimideHCID 516892Sodium BicarbonateHCID 2795462Pyrazolo(1,5-a)pyridine-3-carboxylic acid

Product 1

HCID 27557863-Bromo-pyrazolo[1,5-a]pyridineYield 76%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

N-Bromosuccinimide (3.06 g, 17.22 mmol) and sodium hydrogen carbonate (4.34 g, 51.66 mmol) were added to a solution of pyrazolo[1,5-a]pyridine-3-carboxylic acid (Preparation 22b, 2.81 g, 17.22 mmol) in NN-dimethylformamide (40 mL) and the resulting mixture was stirred at room temperature for 4 h before being poured over 100 mL of water. The resulting suspension was extracted twice with ethyl acetate and the combined organic layers were dried over magnesium sulphate, filtered and the solvent was evaporated. The crude product was purified by flash chromatography (8:2 hexane/ethyl acetate) to yield the title compound (2.58 g, 76%).

Workup

  1. extractionThe resulting suspension was extracted twice with ethyl acetate
  2. dry with materialthe combined organic layers were dried over magnesium sulphate
  3. filtrationfiltered
  4. customthe solvent was evaporated
  5. customThe crude product was purified by flash chromatography (8:2 hexane/ethyl acetate)

Sources & evidence

ORD record
ord-0a16192b7d24457a8d803ef48edc5929
Source dataset
uspto-grants-2015_12
Patent number
US09206183B2

Reaction notes

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