Trifluoroacetic anhydride → 7-Bromoimidazo(1,5-a)pyridine

Participants

Reaction Conditions

Reaction Steps

To a 100-mL round-bottom flask, was placed a solution of N-((4-bromopyridin-2-yl)methyl)formamide (compound 39.2, 3.0 g, 90%, 12.6 mmol) in dichloromethane (20 mL). The solution was cooled to 0-5° C. then trifluoroacetic anhydride (1.93 mL, 13.9 mmol) was added drop-wise. The resulting solution was stirred for 1 h at room temperature, then the pH was adjusted to 7 by careful and slow addition of aqueous sodium carbonate (sat.). The aqueous phase was extracted with dichloromethane (3×20 mL) and the combined organic layers were washed with brine (3×20 mL), dried (Na2SO4), filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography with ethyl acetate/petroleum ether (1/1) as the eluent to yield the title compound as a brown solid (1.0 g, 40%).

Provenance & Evidence