反应详情

tert-Butyl magnesium bromide (2M tetrahydrofuran solution; 35 ml) was added to a suspension of copper cyanide (3.1 g) in tetrahydrofuran (35 ml) at −78° C., stirred for 20 minutes, and then 1-(5-bromopyridin-2-yl)-5-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (3.1 g) described in Reference example 24(2) was added and the mixture was stirred at −78° C. for two hours. It was further stirred at room temperature for 16 hours. Ammonium hydroxide was added to the reaction solution and extracted with ethyl acetate. The organic layer was washed with water and saturated brine, dried over anhydrous sodium sulfate and concentrated in vacuo. The resulting residue was purified with silica gel column chromatography (n-hexane/ethyl acetate) to give 1-(5-tert-butylpyridin-2-yl)-5-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (320 mg) as a yellow oil.

1. additionwas added
2. stirringthe mixture was stirred at −78° C. for two hours
3. stirringIt was further stirred at room temperature for 16 hours
4. extractionextracted with ethyl acetate
5. washThe organic layer was washed with water and saturated brine
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated in vacuo
8. customThe resulting residue was purified with silica gel column chromatography (n-hexane/ethyl acetate)