Dimethylformamide → Ethyl 2-(3-((trimethylsilyl)ethynyl)pyrazin-2-yl)acetate

Participants

Reaction Conditions

Reaction Steps

A mixture of the ethyl 2-(3-chloropyrazin-2-yl)acetate (I99) (0.410 g, 2.04 mmol), DMF (6 mL), triethylamine (2 mL), bis(triphenylphosphine)palladium(II) chloride (72 mg, 5 mol %) and copper(I) iodide (19 mg, 5 mol %) in a Schlenk tube was degassed with three vacuum/nitrogen cycles, then trimethylsilylacetylene (0.866 mL, 6.13 mmol) was added under nitrogen. The tube was flushed with nitrogen, sealed and heated to 90° C. After 18 hours the mixture was cooled and poured into water (50 mL). Saturated ammonium chloride (50 mL) was added, and the mixture was extracted with diethyl ether (3×100 mL). The combined ether phases were washed with brine, dried (sodium sulphate) and evaporated. The residue was chromatographed (40 g silica cartridge, 0-30% ethyl acetate/petroleum benzine 40-60° C.) to give the title compound (I100) (0.386 g, 72% yield) as a yellow oil; 1H NMR (400 MHz, CDCl3) δ 8.47-8.41 (m, 2H), 4.20 (q, J=7.1 Hz, 2H), 4.05 (s, 2H), 1.26 (t, J=7.1 Hz), 0.28 (s, 9H). LCMS Method C: rt 6.20 min; m/z 263.1 [M+H]+.

Provenance & Evidence