Triethylamine → 4-Chloro-5-(phenylethynyl)pyrimidine

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Reaction Steps

A mixture of 2.1 g of 4-chloro-5-iodopyrimidine, 10 mL of triethylamine, 1.2 mL phenylacetylene, 80 mg copper iodide and 160 mg of dichlorobis(triphenylphosphine was stirred at room temperature for 18 hours. The mixture was diluted with dichloromethane and evaporated in vacuo. The residue was redissolved in a few mL of dichloromethane, 10 mL of triethylamine added and the mixture heated at reflux for one hour. The heterogeneous mixture was evaporated in vacuo and the residue obtained was partitioned between water and dichloromethane. A gelatinous precipitate which formed on shaking the two layers was filtered off, enabling separation of the two layers. The organic extracts were dried over sodium sulfate, filtrated and evaporated in vacuo to yield 2.5 g of a dark brown syrup. The syrup was purified by column chromatography on silica gel, twice, eluting with hexanes, 1:1 hexanes/dichloromethane, dichloromethane and finally ethyl acetate. Like fractions from dichloromethane elution were pooled, obtaining 350 mg of the product, 5-phenylethynyl-4-chloropyrimidine as an oil which solidified to white rosettes.

Provenance & Evidence