Acetic Acid → HCID 19839443, compound

HRID 1638902Notes

Reaction equation

HRID 1638902 reaction equation
N[C:2]1[C:6]([Br:7])=[CH:5][N:4]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][N:9]=2)[N:3]=1.[N:14]([O-])=O.[Na+].C(O)(=O)C.[S:22](=[O:24])=[O:23]>Cl.ClCCCl.O>[Br:7][C:6]1[C:2]([S:22]([NH2:14])(=[O:24])=[O:23])=[N:3][N:4]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][N:9]=2)[CH:5]=1

Participants

8

Reactant 4

HCID 176Acetic AcidHCID 1119Sulfur DioxideHCID 19839389HCID 19839389, compoundHCID 23668193Sodium Nitrite

Product 1

HCID 19839443HCID 19839443, compoundYield 93%

Reagents, catalysts & solvents 3

HCID 111,2-DichloroethaneSolventHCID 313Hydrochloric AcidSolventHCID 962WaterSolvent

Procedure

3 g of 3-amino-4-bromo-1-(2-pyridyl)pyrazole was suspended in 60 ml of hydrochloric acid, to which 2.5 ml of an aqueous solution containing 1.2 g of sodium nitrite was added dropwise at -10° to -5° C. to prepare a solution of diazonium salt. This solution of diazonium salt was added dropwise at 5° C. to 30 ml of acetic acid saturated with sulfur dioxide containing 0.5 g of cuprous chloride. After stirring at room temperature for 20 minutes, 100 ml of water and 300 ml of 1,2-dichloroethane were added and stirred to separate an organic layer. To the organic layer, added was 10 ml of 28% ammonia water, followed by vigorous stirring at room temperature for 1 hour. Thereafter, solvent was evaporated under reduced pressure and 200 ml of ethyl acetate was added. After further stirring, insolubles were filtered off and ethyl acetate was evaporated to obtain 2.2 g of the title compound as a crude product. This crude product was purified by a silica gel column chromatography (developed with ethyl acetate) to obtain 0.5 g of the title compound as a pure product. m.p.: 201° to 203° C.

Workup

  1. additionwas added dropwise at -10° to -5° C.
  2. stirringstirred
  3. customto separate an organic layer
  4. additionTo the organic layer, added
  5. stirringby vigorous stirring at room temperature for 1 hour
  6. customThereafter, solvent was evaporated under reduced pressure and 200 ml of ethyl acetate
  7. additionwas added
  8. stirringAfter further stirring
  9. filtrationinsolubles were filtered off
  10. customethyl acetate was evaporated

Sources & evidence

ORD record
ord-aa877fbc5b984513b82888016d2bc955
Source dataset
uspto-grants-1989_11
Patent number
US04881965

Reaction notes

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