Sodium Carbonate → 1-ethyl-4-iodo-3-(2-thienyl)-1H-pyrazole

HRID 2359085Notes

Reaction equation

HRID 2359085 reaction equation
[CH2:1]([N:3]1[CH:7]=[CH:6][C:5]([C:8]2[S:9][CH:10]=[CH:11][CH:12]=2)=[N:4]1)[CH3:2].[I:13]N1C(=O)CCC1=O.S([O-])([O-])(=O)=S.[Na+].[Na+].C(=O)([O-])[O-].[Na+].[Na+]>CN(C)C=O>[CH2:1]([N:3]1[CH:7]=[C:6]([I:13])[C:5]([C:8]2[S:9][CH:10]=[CH:11][CH:12]=2)=[N:4]1)[CH3:2]

Participants

6

Reactant 4

HCID 10340Sodium CarbonateHCID 24477Sodium ThiosulfateHCID 120273N-Iodosuccinimide2×HCID 672609041-ethyl-3-(2-thienyl)-1H-pyrazole

Product 1

HCID 672606401-ethyl-4-iodo-3-(2-thienyl)-1H-pyrazoleYield 51.1%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of 1-ethyl-3-(2-thienyl)-1H-pyrazole (13.5 mmol) in 45 mL dry N,N-dimethylformamide under argon atmosphere was added N-iodosuccinimide (14.1 mmol) in small portions. The reaction mixture was stirred overnight at room temperature. N-Iodosuccinimide (4.4 mmol) was added and stirring was continued for 24 h. 5% aqueous sodium thiosulfate solution and saturated aqueous sodium carbonate solution were added and the mixture was stirred at room temperature for 1 h, then extracted with ethyl acetate. The combined organic extracts were successively washed with water and brine, dried over MgSO4, filtered and concentrated. The residue was purified by chromatography on silica gel (toluene:ethyl acetate 100:0 to 0:100) to afford 2.10 g 1-ethyl-4-iodo-3-(2-thienyl)-1H-pyrazole (51% yield).

Workup

  1. stirringstirring
  2. waitwas continued for 24 h
  3. stirringthe mixture was stirred at room temperature for 1 h
  4. extractionextracted with ethyl acetate
  5. washThe combined organic extracts were successively washed with water and brine
  6. dry with materialdried over MgSO4
  7. filtrationfiltered
  8. concentrationconcentrated
  9. customThe residue was purified by chromatography on silica gel (toluene:ethyl acetate 100:0 to 0:100)

Sources & evidence

ORD record
ord-962394ccc3214294bb16962b627c7cdf
Source dataset
uspto-grants-2014_04
Patent number
US08685974B2

Reaction notes

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