Dichloromethane → tert-butyl 4-(5-chloro-2-hydroxyphenyl)-1H-pyrazole-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A suspension of 4-chloro-2-iodophenol (200 mg, 0.78 mmol) and potassium carbonate (434 mg, 3.14 mmol) in 1,4-dioxane (3 mL) and water (1 mL) was degassed and heated for 1 hour at 50° C. tert-Butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole-1-carboxylate (347 mg, 1.18 mmol) and palladium (0) tetrakis(triphenylphoshine) (91 mg, 0.08 mmol) were added and the mixture heated at 50° C. for 5 hours. Dichloromethane (20 ml) and water (10 ml) were added and the organics separated and evaporated in vacuo. The residue was purified by column chromatography (silica gel) eluting with ethyl acetate:heptane (2:8 to 1:0, by volume) to afford the title product as a white solid, 155 mg, 66% yield.

Provenance & Evidence