Ammonium Chloride → 5-(2,6-difluorophenyl)-1-methyl-1H-pyrazole-3-carbonitrile

Participants

Reaction Conditions

Reaction Steps

To a mixture of ammonium chloride (0.42 g, 7.52 mmol) in toluene (10 mL) at 0° C. was added dropwise trimethyl aluminum (2 M in toluene, 3.76 mL, 7.52 mmol). After the addition was complete, the reaction mixture was stirred at 0° C. for 1 h, warmed to room temperature, and then a mixture of ethyl 5-(2,6-difluorophenyl)-1-methyl-1H-pyrazole-3-carboxylate (i.e. the product of Step A) (1 g, 3.76 mmol) in toluene (5 mL) was added and the mixture was heated at 110° C. for 4 h. The reaction mixture was allowed to cool to room temperature, partitioned between aqueous hydrochloric acid (1 N) and diethyl ether (about 20 mL) and the organic phase was separated. The aqueous phase was extracted with diethyl ether and the combined organic layers were dried over magnesium sulfate, filtered and concentrated under reduced pressure. The resulting material was purified by silica gel column chromatography (10 to 20% gradient of ethyl acetate in hexanes) to provide the title compound as a solid (0.4 g).

Provenance & Evidence