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

HRID 1600361Notes

Reaction equation

HRID 1600361 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 94.4%

Conditions

Temperature
40 °C

Procedure

60 parts (0.5 mol) of acetophenone and 53 parts (0.5 mol) of benzaldehyde were simultaneously added dropwise at 40° C. to 326.7 parts (2.0 mol) of 60% strength by weight sulfuric acid in the course of 30 minutes. The mixture was stirred at 40° C. for 30 minutes and the phases were then separated. The sulfuric acid phase was initially introduced intoa four-necked flask with 0.5 parts (0.0033 mol) of sodium iodide and heatedto 130° C. The upper phase was then simultaneously added dropwise with 25 parts (0.5 mol) of hydrazine hydrate in the course of 30 minutes. The temperature fell from 130° C. to 120° C. during the addition. The temperature was again brought to 130° C. by distilling off water and kept at 130° C. for 2 hours by further distillation of water. The amount of water distilled off was 70 ml. The mixture was diluted at 100° C. with 250 ml of water and neutralizedat 70° C. with 497 parts (3.1 mol) of 25% strength sodium hydroxide solution. The precipitate was filtered off with suction at 25° C. and washed with water until sulfate-free. After drying, 105.5 parts of 3,5-diphenylpyrazole were obtained having a purity of 98.5% (HPLC), which corresponds to a yield of 94.4% of theory. M.p.: 199° C.

Workup

  1. customthe phases were then separated
  2. customheatedto 130° C
  3. additionThe temperature fell from 130° C. to 120° C. during the addition
  4. customwas again brought to 130° C.
  5. distillationby distilling off water
  6. distillationkept at 130° C. for 2 hours by further distillation of water
  7. distillationThe amount of water distilled off
  8. additionThe mixture was diluted at 100° C. with 250 ml of water and neutralizedat 70° C. with 497 parts (3.1 mol) of 25% strength sodium hydroxide solution
  9. filtrationThe precipitate was filtered off with suction at 25° C.
  10. washwashed with water until sulfate-free
  11. customAfter drying

Sources & evidence

ORD record
ord-f71ccfd1f927467598282dd15940523f
Source dataset
uspto-grants-1998_04
Patent number
US05744614

Reaction notes

Loading…