Methylhydrazine → 1,5-Dimethyl-3-(trifluoromethyl)pyrazole

HRID 327019Notes

Reaction equation

HRID 327019 reaction equation
[F:1][C:2]([F:10])([F:9])[C:3](=O)[CH2:4][C:5](=O)[CH3:6].[CH3:11][NH:12][NH2:13]>C(O)C>[CH3:11][N:12]1[C:5]([CH3:6])=[CH:4][C:3]([C:2]([F:10])([F:9])[F:1])=[N:13]1

Participants

4

Reactant 2

HCID 6061MethylhydrazineHCID 739431,1,1-Trifluoro-2,4-pentanedione

Product 1

HCID 127475251,5-Dimethyl-3-(trifluoromethyl)pyrazoleYield 95%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Procedure

To a solution 25.0 grams of 1,1,1,-trifluoro-2,4-pentanedione in 150 ml of ethanol (anhydrous, 5% methanol) at 10 C. was added dropwise over 35 minutes a solution 8.3 grams of methyl hydrazine in 25 ml of ethanol. The reaction temperature did not exceed 20 C. After an additional 30 minutes of stirring, the cooling bath was removed and the reaction was allowed to stir for one hour. Then five ml of glacial acetic acid was added and the reaction was refluxed for four hours. The reaction was then concentrated under reduced pressure and 100 ml of toluene was added to help azeotrope the residual acetic acid during a second concentration under reduced pressure. High vacuum was pulled on the sample for one hour at 50 C. to yield 25.3 g of the desired product as an oil.

Workup

  1. customthe cooling bath was removed
  2. stirringto stir for one hour
  3. additionThen five ml of glacial acetic acid was added
  4. temperaturethe reaction was refluxed for four hours
  5. concentrationThe reaction was then concentrated under reduced pressure and 100 ml of toluene
  6. additionwas added
  7. concentrationduring a second concentration under reduced pressure
  8. waitHigh vacuum was pulled on the sample for one hour at 50 C

Sources & evidence

ORD record
ord-f4f3b45936844500a753d4a94cbf349a
Source dataset
uspto-grants-1993_12
Patent number
US05272128

Reaction notes

Loading…