Hydrazine hydrate (1:1) → 4-(1-benzyl-1H-imidazol-2-ylmethyl)-3,5-diethyl-1H-pyrazole

HRID 254543Notes

Reaction equation

HRID 254543 reaction equation
[CH2:1]([N:8]1[CH:12]=[CH:11][N:10]=[C:9]1[CH2:13][CH:14]([C:19](=O)[CH2:20][CH3:21])[C:15](=O)[CH2:16][CH3:17])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.O.[NH2:24][NH2:25]>C(O)C>[CH2:1]([N:8]1[CH:12]=[CH:11][N:10]=[C:9]1[CH2:13][C:14]1[C:19]([CH2:20][CH3:21])=[N:24][NH:25][C:15]=1[CH2:16][CH3:17])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 24654Hydrazine hydrate (1:1)HCID 589518614-(1-benzyl-1H-imidazol-2-ylmethyl)-heptane-3,5-dione

Product 1

HCID 589516844-(1-benzyl-1H-imidazol-2-ylmethyl)-3,5-diethyl-1H-pyrazole

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Procedure

To a solution of 140 mg (0.47 mmol) 4-(1-benzyl-1H-imidazol-2-ylmethyl)-heptane-3,5-dione in 1.5 ml ethanol was added a solution of 24 mg (0.48 mmol) hydrazine monohydrate in 0.5 ml ethanol and the mixture heated to reflux for 10 min. The reaction mixture was evaporated under reduced pressure, the residue dissolved in 1N aqueous HCl solution and extracted three times with t-butyl methyl ether. The aqueous phase was adjusted to pH 12 and extracted three times with t-butyl methyl ether, the combined extracts washed with brine, dried over sodium sulfate, filtered and evaporated. Purification of the residue by flash-chromatography on silica gel with ethyl acetate as eluent provided 4-(1-benzyl-1H-imidazol-2-ylmethyl)-3,5-diethyl-1H-pyrazole as colourless viscous oil: MS (ISP): 295.3 ((M+H)+.).

Workup

  1. temperaturethe mixture heated
  2. temperatureto reflux for 10 min
  3. customThe reaction mixture was evaporated under reduced pressure
  4. dissolutionthe residue dissolved in 1N aqueous HCl solution
  5. extractionextracted three times with t-butyl methyl ether
  6. extractionextracted three times with t-butyl methyl ether
  7. washthe combined extracts washed with brine
  8. dry with materialdried over sodium sulfate
  9. filtrationfiltered
  10. customevaporated
  11. customPurification of the residue by flash-chromatography on silica gel with ethyl acetate as eluent

Sources & evidence

ORD record
ord-89f7b455f2c54a6eab0746251609f0e2
Source dataset
uspto-grants-2011_01
Patent number
US07875645B2

Reaction notes

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