Lithium Bromide → N-(4(5-bromopent-1-yn-1-yl)phenyl)-2,2,2-trifluoroacetamide

Participants

Reaction Steps

A solution of N-(4-(5-chloropent-1-ynyl)phenyl)-2,2,2-trifluoroacetamide (10 mmol, prepared analogously to Intermediate 39, employing 5-chloropentyne in place of 5-hexyn-1-ol) in 3-pentanone (200 mL) was treated with lithium bromide (10 eq, 100 mmol). The mixture was heated to reflux for 16 hours, followed by concentration to dryness under reduced pressure. The residue was taken up in ethyl acetate and washed with water. The concentrated organic phase was taken up again in 3-pentanone (200 mL) and heated to reflux for four hours in the presence of lithium bromide (10 eq, 100 mmol). The mixture was concentrated to dryness under reduced pressure. The residue was partitioned between ethyl acetate and water. The organic phase was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated to dryness under reduced pressure. The crude product was purified via automated flash silica gel chromatography, using a 40 g Silicycle SiliSep flash column (hexanes/ethyl acetate). Concentration of the desired fractions under reduced pressure provided the title compound as an off-white solid. ES/MS calcd. for C13H12BrF3NO+ 334.0. Found m/z=334.1 (M+H)+.

Provenance & Evidence