Pyrimidine, 2,4-dichloro-5-methyl- → 2-chloro-5-methyl-4-[[3-(trifluoromethyl)phenyl]methyl]pyrimidine

Participants

Reaction Steps

To a suspension of zinc dust (2.5 g, 38 mmol) stirred in 25 mL of tetrahydrofuran were added 2 drops of 1,2-dibromoethane and the mixture was heated to reflux. The suspension was then cooled and 2 drops of trimethylsilyl chloride were added followed by portionwise addition of 3-(trifluoromethyl)benzyl bromide (6.0 g, 25 mmol) with heating. When the reaction temperature reached 55° C., a strong exotherm occurred and the reaction mixture was allowed to heat at reflux. The cooled reaction solution was decanted into a solution of 2,4dichloro-5-methylpyrimidine (3.3 g, 20 mmol) and dichlorobis(triphenylphosphine)palladium(II) (0.44 g, 0.63 mmol) stirring in 15 mL of tetrahydrofuran. Upon heating, the reaction mixture exothermed strongly again at 55° C. and was then heated to reflux. The reaction mixture was allowed to cool and partitioned between diethyl ether and water. The organic layer was separated, washed with 1 N aqueous hydrochloric acid and brine, dried over magnesium chloride and concentrated under reduced pressure to give a crude oil. Purification by flash chromatography on silica gel (15 to 25% ethyl acetate in hexane) yielded 2.4 g of the title compound of Step A as an oil. 1H NMR (CDCl3): δ8.35 (s, 1H), 7.60-7.35 (m, 4H), 4.15 (s, 2H), 2.25 (s, 3H).

Provenance & Evidence