Trimethylsilyldiazomethane → 4-Phenyl-5-(trimethylsilyl)-1H-pyrazole-3-carbonitrile

HRID 1951461Notes

Reaction equation

HRID 1951461 reaction equation
C([Li])CCC.[CH3:6][Si:7]([CH:10]=[N+:11]=[N-:12])([CH3:9])[CH3:8].[CH:13](=[C:20](C#C)[C:21]#[N:22])[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1>C1COCC1.C(OCC)(=O)C>[C:14]1([C:13]2[C:20]([C:21]#[N:22])=[N:12][NH:11][C:10]=2[Si:7]([CH3:9])([CH3:8])[CH3:6])[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1

Participants

6

Reactant 3

HCID 167693TrimethylsilyldiazomethaneHCID 860306562-Benzylidene-but-3-ynenitrileHCID 178418339Butyllithium

Product 1

HCID 131447894-Phenyl-5-(trimethylsilyl)-1H-pyrazole-3-carbonitrileYield 69.1%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent2×HCID 8857Ethyl AcetateSolvent

Procedure

n-Butyl lithium (2.7 M solution in heptane) (3.3 ml, 9 mmol) was added drop wise to a stirred solution of trimethylsilyl diazomethane (2 M solution in diethyl ether) (4.5 ml, 9 mmol) in anhydrous THF (10 ml) at −78° C. under a nitrogen atmosphere, then stirred for a further 30 minutes. To this was added drop wise a solution of 2-benzylidene-but-3-yne nitrile (920 mg; 6 mmol) in anhydrous THF (5 ml), the mixture stirred for 30 minutes at −78° C. then gradually allowed to warm to room temperature overnight. The reaction mixture was diluted with ethyl acetate (30 ml) then washed with saturated ammonium chloride solution followed by brine. The ethyl acetate layer was separated, dried (MgSO4), filtered and evaporated. The crude product was purified by flash column chromatography eluting with 1:8 then 1:4 ethyl acetate/hexane and the product containing fractions combined and evaporated to give 1.0 g of 4-phenyl-5-trimethylsilanyl-1H-pyrazole-3-carbonitrile.

Workup

  1. stirringthe mixture stirred for 30 minutes at −78° C.
  2. washthen washed with saturated ammonium chloride solution
  3. customThe ethyl acetate layer was separated
  4. dry with materialdried (MgSO4)
  5. filtrationfiltered
  6. customevaporated
  7. customThe crude product was purified by flash column chromatography
  8. washeluting with 1:8
  9. addition1:4 ethyl acetate/hexane and the product containing fractions
  10. customevaporated

Sources & evidence

ORD record
ord-74655e5087ae4ac68bc239d38164dd1f
Source dataset
uspto-grants-2013_03
Patent number
US08404718B2

Reaction notes

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