Acetic Anhydride → N-[5-Bromo-4-(trifluoromethyl)-2-pyridinyl]acetamide

Participants

Reaction Conditions

Reaction Steps

A dry vessel under nitrogen at room temperature was charged with 5-bromo-4-(trifluoromethyl)pyridin-2-amine B1 (200 g, 830 mmol) and ethyl acetate (200 ml). The reaction mixture was cooled to 0° C. To the solution was added N,N-dimethylpyridin-4-amine (1.01 g, 8.29 mmol). Heptane (400 ml) was added and the mixture was cooled to 0° C. Acetic anhydride (109.6 ml, 1162 mmol) was added over a period of 60 min. The reaction mixture was warmed to 50° C. within 60 min. The reaction mixture was stirred at 50° C. for 18 h. Solvent (330 g) was removed by distillation (540-250 mbar, 50° C.) until a residue of ˜300 ml was obtained. The reaction mixture was allowed to cool to 20° C. Heptane (800 ml) was added and the mixture was stirred for 30 min. The precipitate was collected by filtration. The filter cake was washed with heptane (100 ml). The product was dried in a tray dryer for 16 h at 40° C., <20 mbar to yield 212 g (90%) B2 as slightly brown solid.

Provenance & Evidence