Potassium Carbonate → Methyl 4-(1-methyl-1H-pyrazol-5-yl)thiophene-2-carboxylate

Participants

Reaction Steps

A solution of methyl 4-bromo-2-thiophenecarboxylate (2.5 g, 11.31 mmol), potassium carbonate (7.81 g, 56.5 mmol), 1-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (2.59 g, 12.44 mmol)[prepared according to Preparation 7] and bis(tri-t-butylphosphine)palladium(0) (0.289 g, 0.56 mmol) in 1,4-dioxane (47 ml) and water (9 ml) was stirred at 80° C. in a sealed tube for 1 h. 1-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (2.59 g, 12.44 mmol) and bis(tri-t-butylphosphine)palladium(0) (0.289 g, 0.56 mmol) were added and the reaction stirred an additional 1 h. The mixture was partitioned between H2O-DCM. The aqueous phase was washed several times with DCM and the combined organic fractions were dried over Na2SO4, concentrated and purified via column chromatography (10-40% EtOAc in hexanes) affording methyl 4-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (2.5 g, 11.25 mmol, 99% yield) as a yellow solid: LCMS (ES) m/e 223 (M+H)+.

Provenance & Evidence