2-chloro-6-(4-chlorophenyl)pyrazine synthesis

Yield:637353-09-4 33%

Reaction Conditions:

with potassium carbonate;tetrakis(triphenylphosphine) palladium⁽⁰⁾ in ethanol;toluene at 65; for 16 h;Inert atmosphere;

Steps:

79.A

2,6-Dichloropyrazine (779 mg, 5.23 mmol), 4-chlorophenylboronic acid (899 mg, 5.75 mmol), and potassium carbonate (2876 μl of a 2 M solution, 5.75 mmol) in toluene-ethanol (4:1, 17 ml) were sparged with argon for 5 minutes. Pd(PPtLs)₄ (604 mg, 0.52 mmol) was added and the mixture was sparged an additional 2 minutes. The reaction was heated to 65° C for 16 hours, then cooled to ambient temperature, concentrated in vacuo, and dissolve in 25 ml ethyl acetate. The ethyl acetate solution was washed with saturated aqueous sodium bicarbonate and brine solution, dried with sodium sulfate, filtered, concentrated, and purified on silica gel. Elution with a gradient of 2-30% ethyl acetate -hexanes provided the title compound (389 mg, 33%) as a white solid.

References:

WO2010/75200,2010,A1 Location in patent:Page/Page column 109-110