Diethyl Ether → 5-Amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-(3-pyridyl)pyrazole

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Reaction Steps

To a rapidly stirred solution of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-iodopyrazole (0.25 g) in toluene (2 ml) containing tetrak-is(triphenylphosphine)palladium(0) (0.02 g) was added saturated aqueous sodium hydrogen carbonate solution (1 ml) and a solution of 3-pyridylboronic acid (0.153 g) in ethanol (1 ml). The mixture was heated under reflux for 5 hours, then left at room temperature ovemight and then poured into ether (25 ml) and water (25 ml). The organic layer was separated, dried (MgSO4) and evaporated. The residue was taken up the minimum amount of ethyl acetate and purified by column chromatography on silica gel (20 g) eluted with dichloromethane:methanol (100:1). Combination and evaporation of suitable fractions followed by recrystallisation from ether gave the title compound as an off-white solid, m.p. 265-7° C.

Provenance & Evidence