Benzaldehyde → 1H-Pyrazole, 3,5-diphenyl-

HRID 1600362Notes

Reaction equation

HRID 1600362 reaction equation
[C:1]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)(=O)[CH3:2].[CH:10](=O)[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1.S(=O)(=O)(O)O.[I-].[Na+].O.[NH2:26][NH2:27]>>[C:11]1([C:10]2[CH:2]=[C:1]([C:4]3[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=3)[NH:27][N:26]=2)[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1

Participants

6

Reactant 5

HCID 240BenzaldehydeHCID 1118Sulfuric Acid2×HCID 5238Sodium IodideHCID 7410AcetophenoneHCID 24654Hydrazine hydrate (1:1)

Product 1

HCID 708401H-Pyrazole, 3,5-diphenyl-Yield 93.1%

Conditions

Temperature
70 °C

Procedure

120 parts (1 mol) of acetophenone and 106 parts (1 mol) of benzaldehyde were simultaneously added dropwise at 70° C. to 490 parts (3 mol) of 60% strength by weight sulfuric acid. The mixture was stirred at 70° C. for 2 hours and the phases were then separated. The sulfuricacid phase was initially introduced with 2 parts (0.0133 mol) of sodium iodide and 62.5 parts (1 mol) of 80% strength by weight hydrazine hydrate were added dropwise. The reaction mixture was heated to reflux (116° C.) and the organic phase was added dropwise in the course of60 minutes. In order to keep the temperature at 116° C., water was distilled off. The mixture was stirred at 116° C. for 5 hours, 150 ml of water being distilled off in this process. The mixture was diluted with 500 ml of water, and the precipitate was filtered off at room 30 temperature and washed with water until neutral. After drying, 213.3 partsof 3,5-diphenylpyrazole having a purity of 96% (HPLC) were obtained, which corresponds to a yield of 93.1% of theory. M.p.: 196° C.

Workup

  1. customthe phases were then separated
  2. additionwere added dropwise
  3. temperatureThe reaction mixture was heated
  4. temperatureto reflux (116° C.)
  5. additionthe organic phase was added dropwise in the course of60 minutes
  6. customat 116° C.
  7. distillationwater was distilled off
  8. stirringThe mixture was stirred at 116° C. for 5 hours
  9. distillation150 ml of water being distilled off in this process
  10. additionThe mixture was diluted with 500 ml of water
  11. filtrationthe precipitate was filtered off at room 30 temperature
  12. washwashed with water until neutral
  13. customAfter drying

Sources & evidence

ORD record
ord-0f73181cf5aa4816b138ef7cf2c09f96
Source dataset
uspto-grants-1998_04
Patent number
US05744614

Reaction notes

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