Triethylamine → 2-Bromo-5-phenylethynyl-pyrazine

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-bromo-5-iodopyrazine (500 mg, 1.76 mmol), phenylacetylene (224 mg, 241 μl, 2.19 mmol, 1.25 equiv.), triethylamine (533 mg, 734 μl, 5.27 mmol, 3 equiv.), bis(triphenylphosphine)palladium (II) chloride (73.9 mg, 0.105 mmol, 0.06 equiv.) and triphenyl-phosphine (13.8 mg, 0.053 mmol, 0.03 equiv.) in 10 ml of THF was added under an Argon atmosphere copper (I) iodide (10.0 mg, 0.053 mmol, 0.03 equiv.). The suspension was warmed to 60° C. overnight, taken up in 5 ml of ethyl acetate and adsorbed on 4 g of silica. Purification by flash chromatography on silicagel using a 2:1 ethyl acetate/heptane mixture yielded the title compound as a light brown solid (107 mg, 23% yield). The material was directly used in the next step without further characterization.

Provenance & Evidence