4-Fluorophenylboronic acid → 3-(4-Fluorophenyl)-1H-indazole-5-carbonitrile

Participants

Reaction Conditions

Reaction Steps

To a solution of 2.0 g of tert-butyl 3-bromo-5-cyano-1H-1-indazolecarboxylate in 30 ml tetrahydrofuran were added 70 mg of palladium(II) acetate, 218 mg of 2-(dicyclohexylphosphino)biphenyl, 1.19 g of potassium fluoride and 1.30 g of 4-fluorophenylboronic acid, and the mixture was stirred at 50° C. for one day. After removing the solvent by distillation, the residue was diluted with 40 ml of ethyl acetate. The mixture was sequentially washed with water and brine, dried over anhydrous magnesium sulfate and the solvent was evaporated. The residue was dissolved in 25 ml of methylene chloride, and 5 ml of trifluoroacetic acid was added, followed by stirring at room temperature for 1 hour. After removing the solvent by distillation, the residue was diluted with 40 ml of ethyl acetate. The mixture was sequentially washed with saturated aqueous sodium hydrogencarbonate solution and brine, dried over anhydrous magnesium sulfate and the solvent was evaporated. The crude product was purified and separated by silica gel column chromatography (ethyl acetate:toluene=1:19 to 1:9), to give 1.09 g of the title compound as bright yellow crystals.

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