Diisopropylamine → (5-bromo-2-fluoro-pyridin-3-yl)-(2-ethyl-2H-pyrazol-3-yl)-methanone

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Reaction Steps

Diisopropylamine and tetrahydrofuran were combined and cooled to −20° C. n-Butyl lithium (2.5M in hexanes) was slowly added and the resulting mixture stirred at this temperature for 30 minutes. The temperature was lowered to −78° C. and neat 5-bromo-2-fluoropyridine was added (internal temperature was not allowed to exceed −68° C.). The reaction mixture was stirred at −78° C. for 40 minutes. The resulting mixture was added to a solution of 2-ethyl-2H-pyrazole-3-carboxylic acid methoxy-methyl-amide in tetrahydro-furan. The combined reaction mixture was stirred at −78° C. for 1 hour before the reaction mixture was slowly warmed to room temperature, and quenched with saturate aqueous ammonium chloride solution. The reaction mixture was extracted with dichloromethane, dried over sodium sulfate, and concentrated. The crude material was purified by flash chromatography on silica gel to afford (5-bromo-2-fluoro-pyridin-3-yl)-(2-ethyl-2H-pyrazol-3-yl)-methanone. MS: m/z 298.1+300.1 (M+H+).

Provenance & Evidence