Sulfuric Acid → pentyl 3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxylate

HRID 1641454Notes

Reaction equation

HRID 1641454 reaction equation
S(=O)(=O)(O)O.[O-]S(OOS([O-])(=O)=O)(=O)=O.[K+].[K+].[Br:18][C:19]1[CH2:23][CH:22]([C:24]([O:26][CH2:27][CH2:28][CH2:29][CH2:30][CH3:31])=[O:25])[N:21]([C:32]2[C:37]([Cl:38])=[CH:36][CH:35]=[CH:34][N:33]=2)[N:20]=1.C(#N)C>O>[Br:18][C:19]1[CH:23]=[C:22]([C:24]([O:26][CH2:27][CH2:28][CH2:29][CH2:30][CH3:31])=[O:25])[N:21]([C:32]2[C:37]([Cl:38])=[CH:36][CH:35]=[CH:34][N:33]=2)[N:20]=1

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 6342AcetonitrileHCID 24412Potassium PersulfateHCID 59549455pentyl 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylate

Product 1

HCID 59549434pentyl 3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxylateYield 47.3%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

0.5 ml of concentrated sulfuric acid and 1.4 g of potassium peroxodisulfate were added to a mixed solution comprising 1.0 g of pentyl 3-bromo-1-(3-chloropyridin-2-yl)-4,5-dihydro-1H-pyrazole-5-carboxylate and 20 ml of acetonitrile, followed by reflux with heating for 3 hours and 20 minutes. After the reaction liquid was stood to cool, the reaction liquid was slowly added to water, followed by stirring for 15 minutes. The mixed liquid was subjected to extraction with ethyl acetate, and the organic layer was washed with a saturated sodium hydrogen carbonate aqueous solution and a sodium chloride aqueous solution and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate=8.5/1.5 to 8/2) to obtain 0.47 g of the oily desired product.

Workup

  1. temperatureby reflux
  2. temperaturewith heating for 3 hours and 20 minutes
  3. customAfter the reaction liquid
  4. temperatureto cool
  5. customthe reaction liquid
  6. extractionThe mixed liquid was subjected to extraction with ethyl acetate
  7. washthe organic layer was washed with a saturated sodium hydrogen carbonate aqueous solution
  8. dry with materiala sodium chloride aqueous solution and dried over anhydrous sodium sulfate
  9. distillationThe solvent was distilled off under reduced pressure
  10. customthe residue was purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate=8.5/1.5 to 8/2)

Sources & evidence

ORD record
ord-032ebdf5381f4ae0978ae90bac72ddb4
Source dataset
uspto-grants-2012_02
Patent number
US08115006B2

Reaction notes

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