3-Chloro-5-(trifluoromethyl)-2-pyridinamine → 8-Chloro-3-methyl-6-(trifluoromethyl)imidazo[1,2-a]pyridine-2-carboxylic acid ethyl ester

Participants

Reaction Steps

To a solution of 2-amino-3-chloro-5-(trifluoromethyl)pyridine (11.3 g, 57.5 mmol) in dioxane (200 mL) at room temperature was added dropwise 3-bromo-2-oxo-butyric acid ethyl ester (12.017 g, 57.49 mmol, the product of Step A). The reaction mixture was heated to reflux for 24 h, cooled, and the dioxane was removed under reduced pressure. Chromatography on silica gel eluting with a hexane/ethyl acetate gradient afforded 17.3 g of 8-chloro-3-methyl-6-(trifluoromethyl)imidazo[1,2-a]pyridine-2-carboxylic acid ethyl ester as a solid.

Provenance & Evidence