ETHANONE, 2-BROMO-1-[3-CHLORO-5-(TRIFLUOROMETHYL)-2-PYRIDINYL]- synthesis

Yield:856245-54-0 46%

Reaction Conditions:

with phenyl-trimethyl-ammonium perbromide in tetrahydrofuran at 20; for 3 h;

Steps:

10

Preparation of 2-bromo-1-[3-chloro-5-(trifluoromethyl)-2-pyridinyl] ethanone; To a solution of 16.6 g (0.074 mol) of 1-[3-chloro-5-(trifluoromethyl)-2-pyridinyl] ethanone in 150 ml of dry tetrahydrofuran, were added portionwise at room temperature 27.8 g (0.074 mol) of phenyltrimethylammonium tribromide. The solution was stirred for 3 hours at room temperature. The formed solid was removed by filtration and the mother liquors were concentrated under vacuum. The resulting orange oil (32.7 g) was purified by flash chromatography on silica gel (eluent: heptane/dichloromethane 3:1) to give 2-bromo-1-[3-chloro-5-(trifluoromethyl)-2-pyridinyl]ethanone: 10.4 g (46 %) as a yellow oil. Mass spectrum: [M-1] = 302.

References:

EP1548007,2005,A1 Location in patent:Page/Page column 44