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1066-54-2

216309-28-3

Example 3: Synthesis of 5-((trimethylsilyl)ethynyl)pyrimidine Tetrakis(triphenylphosphine)palladium(0) (727 mg, 0.6 mmol) was added to a stirred, degassed toluene suspension of 5-bromopyrimidine (5.0 g, 31.4 mmol) and cuprous(I) iodide (120 mg, 0.6 mmol) under nitrogen protection. Diisopropylamine (1:1, 200 mL) was then added. The reaction mixture was heated to 60 °C and then trimethylmethylsilylacetylene (4.89 mL, 34.6 mmol) was slowly added. The reaction mixture was stirred continuously at 60 °C for 3 hours. After completion of the reaction, the mixture was cooled to room temperature and diluted with ether. It was washed sequentially with ethyl acetate (200 mL) and saturated aqueous ammonium chloride solution (3 x 100 mL). The organic layer was separated and dried with anhydrous magnesium sulfate and subsequently concentrated under reduced pressure. The crude product was purified by fast column chromatography (5% ethyl acetate/heptane as eluent) to afford 5-((trimethylmethylsilyl)ethynyl)pyrimidine as a light brown solid in a yield of 4.71 g (85% yield). Liquid chromatography (LC) detection conditions: wavelength 215 nm; retention time (Rt) 2.07 min, purity 88%. Mass spectrum (ES+): m/z 177 ([M+H]+).