Acetic Acid → 3-Bromo-2-ethyl-4H-pyrido[1,2-a]pyrimidin-4-one

Participants

Reaction Steps

A solution of aminopyridine (32.6 g, 347 mmol), ethyl propionylacetate (50.0 g, 347 mmol) and AcOH (250 ml) were heated at reflux overnight. The solution was cooled to room temperature and was added additional 250 ml of acetic acid. The reaction was cooled in a water batch. The resulting solution was treated with 17.8 ml of bromine drop-wise over approximately 10 min. After stirring at room temperature for 2 hours. The precipitate was filtered. The solid was washed with ether two times and 40% ethyl acetate-hexanes once and dried in vacuum to give 31.5 g K2 as the first crop. The filtrate was concentrated to a small volume and the precipitate was filtered. The solid was washed with ether two times and 40% ethyl acetate-hexanes once and dried in vacuum to give 47.1 g of K2 as the second crop. Combined yield: 89.9% over two steps.

Provenance & Evidence