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 27 h 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