Tributylvinyltin → 6-Amino-2-chloro-5-vinylpyrimidine-4-carboxylic acid methyl ester

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Reaction Steps

6-Amino-2-chloro-5-iodopyrimidine-4-carboxylic acid methyl ester (10 g, 32 mmol) was dissolved in 1,2-dichloroethane (100 mL), treated with vinyltributylstannane (11.6 mL, 12.6 g, 40 mmol) and sparged with a nitrogen stream for 10 min. Bis(triphenylphosphine)palladium(II) dichloride (1.1 g, 1.6 mmol, 5 mole %) was added and the mixture was heated at reflux under a nitrogen atmosphere for 3 h. The mixture was cooled, stirred with 10% aqueous KHF2 for 30 min, and filtered through diatomaceous earth to remove solids. The filter cake was washed with more 1,2-dichloroethane and ethyl acetate. The combined filtrates were washed with water, washed with saturated NaHCO3, washed with brine, dried, and evaporated. The crude material was chromatographed on silica (5-20% ethyl acetate/dichloromethane containing 2% acetic acid) to give the title compound (4.5 g, 70% yield). This material contained approximately 5% PPh3, but was used without further purification. MS: m/z=213. 1H NMR (CDCl3) δ 6.77 (dd, 1H), 6.4 (br, 2H), 5.70 (d, 1H), 5.61 (d, 1H).

Provenance & Evidence