4,4-Difluoro-1-(4-trifluoromethylphenyl)butane-1,3-dione → 4-Difluoromethyl-2-(4-trifluoromethyl-phenyl)-imidazo[1,5-a]pyrimidine-8-carboxylic acid ethyl ester

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Reaction Steps

A mixture of 4,4-difluoro-1-(4-trifluoromethyl-phenyl)-butane-1,3-dione (8.87 g, 33.3 mmol) and 5-amino-1H-imidazole-4-carboxylic acid ethyl ester (5.17 g, 33.3 mmol) in acetic acid (100 ml) was refluxed for 27h and evaporated. The crude product was further purified by column chromatography on silica gel (ethyl acetate/heptane 7:3) and crystallization (diethyl ether/hexane) to yield 4-difluoromethyl-2-(4-trifluoromethyl-phenyl)-imidazo[1,5-a]pyrimidine-8-carboxylic acid ethyl ester (6.35 g, 49%) as a yellow solid. MS (EI) 385.1 [(M)+]; mp 219° C.

Provenance & Evidence