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

Participants

Reaction Steps

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+).

Provenance & Evidence