Sodium Carbonate → 5-(2,6-Difluoro-3-nitrophenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole

Participants

Reaction Steps

To a solution of tetrakis(triphenylphosphine)palladium(0) (1.2 g, 1.04 mmol) in dimethoxyethane (30 mL), 2-bromo-1,3-difluoro-4-nitrobenzene (2.38 g, 10 mmol) in dimethoxyethane (20 mL) was added and the mixture was insufflated with nitrogen for 10 min. To the solution, 1-(tetrahydro-2H-pyran-2-yl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (4 g, 15 mmol) in dimethoxyethane (30 mL) was added and the mixture was insufflated with nitrogen for 2 min, then 2 M sodium carbonate solution (40 mL) was added and the mixture was refluxed for 4 h. The mixture was cooled and the organic phase was concentrated to oil. By addition of diethyl ether a precipitate was obtained, filtered off and discarded. The filtrate was concentrated and purified by flash chromatography (eluant: dichloromethane/ethyl acetate 20:1). The title compound was obtained as oil (1.27 g, 40%).

Provenance & Evidence