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

HRID 1600363Notes

Reaction equation

HRID 1600363 reaction equation
S(=O)(=O)(O)O.[I-].[Na+].[C:8]([C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)(=O)[CH3:9].[CH:17](=O)[C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1.O.[NH2:26][NH2:27]>>[C:18]1([C:17]2[CH:9]=[C:8]([C:11]3[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=3)[NH:27][N:26]=2)[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1

Participants

6

Reactant 5

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

Product 1

HCID 708401H-Pyrazole, 3,5-diphenyl-Yield 94.3%

Conditions

Temperature
124 °C

Procedure

392 parts (2 mol) of 50% strength sulfuric acid and 1 part (0.0067 mol) of sodium iodide were initially introduced into the stirring flask. 60 parts (0.5 mol) of acetophenone, 53 parts (0.5 mol) of benzaldehyde and 25 parts(0.5 mol) of hydrazine hydrate were simultaneously added dropwise under reflux at 124° C. in the course of 30 minutes. The temperature fellto 112° C. By distilling off water, the temperature was brought to 130° C. and the mixture was stirred at 130° C. for 60 minutes. 120 ml of water were distilled off. The reaction mixture obtainedwas diluted with 250 ml of water and neutralized with 525 parts (3.28 mol) of 25% strength by weight sodium hydroxide solution and filtered. The filter residue was washed with water until sulfate-free and dried. 110.2 parts of 3,5-diphenylpyrazole having a purity of 94.1% (HPLC) were obtained, which corresponds to a yield of 94.3% of theory. M.p.: 194° C.

Workup

  1. customfellto 112° C
  2. distillationBy distilling off water
  3. customwas brought to 130° C.
  4. distillation120 ml of water were distilled off
  5. additionThe reaction mixture obtainedwas diluted with 250 ml of water and neutralized with 525 parts (3.28 mol) of 25% strength by weight sodium hydroxide solution
  6. filtrationfiltered
  7. washThe filter residue was washed with water until sulfate-free
  8. customdried

Sources & evidence

ORD record
ord-25e736fbb11b4c958fc9574e7d25a3b5
Source dataset
uspto-grants-1998_04
Patent number
US05744614

Reaction notes

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