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

HRID 1600365Notes

Reaction equation

HRID 1600365 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.O.[NH2:24][NH2:25].[I-].[Na+]>>[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:25][N:24]=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 96.5%

Conditions

Temperature
25 °C

Procedure

60 parts (0.5 mol) of acetophenone and 53 parts (0.5 mol) of benzaldehyde were simultaneously added dropwise at 25° C. to 140 parts (1 mol) of initially introduced 70% strength by weight sulfuric acid. The mixture was stirred at 25° C. for 60 minutes and the reaction solution obtained was simultaneously added dropwise with 25 parts (0.5 mol) of hydrazine hydrate at 135° C. to 140 parts (1 mol) of initially introduced 70% strength by weight sulfuric acid and 0.5 parts (0.0033 mol)of sodium iodide in the course of 25 minutes. The mixture was stirred at 125° C. for 60 minutes. In order to keep the temperature at 135° C., 38 parts of water were distilled off. The mixture was diluted with 500 parts of water and neutralized with 247.8 parts (3.1 mol)of 50% strength by weight sodium hydroxide solution. After filtering off the solid it was washed until sulfate-free and dried. 109.7 parts of 3,5-diphenylpyrazole having a purity of 96.8% (HPLC) were obtained, which corresponds to a yield of 96.5% of theory. M.p.: 197° C.

Workup

  1. customthe reaction solution obtained
  2. stirringThe mixture was stirred at 125° C. for 60 minutes
  3. customat 135° C.
  4. distillation38 parts of water were distilled off
  5. additionThe mixture was diluted with 500 parts of water and neutralized with 247.8 parts (3.1 mol)of 50% strength by weight sodium hydroxide solution
  6. filtrationAfter filtering off the solid it
  7. washwas washed until sulfate-free
  8. customdried

Sources & evidence

ORD record
ord-f1cab3c0e57c42fbbbafac9c5e7269f6
Source dataset
uspto-grants-1998_04
Patent number
US05744614

Reaction notes

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