2,5-Dibromothiophene → 2-Bromo-5-(2-pyrazolyl)thiophene

HRID 2109475Notes

Reaction equation

HRID 2109475 reaction equation
[Br:1][C:2]1[S:3][C:4](Br)=[CH:5][CH:6]=1.C([Sn](CCCC)(CCCC)[N:13]1[CH:17]=[CH:16][CH:15]=[N:14]1)CCC>C1(C)C=CC=CC=1.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[Br:1][C:2]1[S:3][C:4]([N:13]2[CH:17]=[CH:16][CH:15]=[N:14]2)=[CH:5][CH:6]=1

Participants

5

Reactant 2

HCID 184532,5-DibromothiopheneHCID 3059331-(Tributylstannyl)-1H-pyrazole

Product 1

HCID 125544912-Bromo-5-(2-pyrazolyl)thiopheneYield 30.6%

Reagents, catalysts & solvents 2

HCID 178418397HCID 178418397, compoundCatalystHCID 1140TolueneSolvent

Procedure

A solution containing 2,5-dibromothiophene (5.0 mL, 10.3 g, 44.4 mmol), 2-(tri-n-butylstannyl)pyrazole (4.09 g, 11.0 mmol), tetrakis(triphenylphosphine)palladium (0) (0.67 g, 0.58 mmol) in toluene (50 mL) was heated under reflux under an argon atmosphere for 6 h. The solution was evaporated and the residue was subjected to flash chromatography on silica using a gradient of 0-25% ethyl acetate/hexane as the eluant. Evaporation of the product-containing fractions gave the sub-title compound (771 mg) as a solid, m/z 241, 243 (MH+).

Workup

  1. temperaturewas heated
  2. temperatureunder reflux under an argon atmosphere for 6 h
  3. customThe solution was evaporated
  4. customEvaporation of the product-containing fractions

Sources & evidence

ORD record
ord-0760d395ae6b411dbb24f629ef4b0ea8
Source dataset
uspto-grants-2009_04
Patent number
US07514567B2

Reaction notes

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