Tributyltin Chloride → 7-(1-Methyl-1-triethylsilanyloxyethyl)-3-(2-trifluoromethylpyrimidin-4-yl)imidazo[1,2-alpha]pyrimidine

Participants

Reaction Conditions

Reaction Steps

A solution of isopropylmagnesium chloride (2.0M in THF, 525 μl, 1.05 mmol) was added dropwise to a stirred suspension of 3-bromo-7-(1-methyl-1-triethylsilanyloxyethyl)imidazo[1,2-α]pyrimidine (370 mg, 1.0 mmol) in THF (5 ml) at −78° C. under N2. The resulting solution was stirred at −78° C. for 15 min and then tributyltin chloride (298 μl, 1.1 mmol) was added. The reaction was warmed to 0° C. and stirred for 1 h. 4-Chloro-2-trifluoromethylpyrimidine (200 mg, 1.1 mmol) and tetrakis(triphenylphosphine)palladium(0) (110 mg, 10 mol %) were added and the reaction heated at reflux for 18 h. The mixture was concentrated under reduced pressure while dry loading onto silica and then purified by column chromatography on silica using 50-80% EtOAc/isohexanes as the eluent to afford 7-(1-methyl-1-triethylsilanyloxyethyl)-3-(2-trifluoromethylpyrimidin-4-yl)imidazo[1,2-α]pyrimidine (136 mg): 1H NMR (400 MHz, CDCl3) δ 10.10 (1H, d, J 7.4), 8.82 (1H, d, J 5.5), 8.57 (1H, s), 7.78 (1H, d, J 5.5), 7.67 (1H, d, J 7.4), 1.70 (6H, s), 1.00 (9H, t, J 8.0), 0.68 (6H, q, J 8.0); m/z (ES+) 438 (M+H+).

Provenance & Evidence