Ammonium Chloride → 1-(5-cyclopropyl-3-fluoropyridin-2-yl)-5-methyl-1H-pyrazole-4-carboxylic acid ethyl ester

Participants

Reaction Steps

A suspension of 1-(5-chloro-3-fluoropyridin-2-yl)-5-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (2 g) in Reference Example 124 (1), cyclopropylboronic acid (911 mg), 1,1′-bis(di-tert-butylphosphino)ferrocene (167 mg), palladium acetate (79 mg) and tripotassium phosphate (4.49 g) in 1,4-dioxane (16 ml) was stirred under reflux. After completion of the reaction, the mixture was allowed to cool, ice water and a saturated aqueous solution of ammonium chloride were added thereto, and the mixture was extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, and the solvent was evaporated in vacuo. The obtained residue was purified with silica gel chromatography (n-hexane/ethyl acetate) to give 1-(5-cyclopropyl-3-fluoropyridin-2-yl)-5-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (1.88 g) as a light brown oil. MS (ESI) m/z: 290 (M+H)+.

Provenance & Evidence