Potassium Carbonate → methyl 5-methyl-4-[1-methyl-4-(1-methylethenyl)-1H-pyrazol-5-yl]-2-thiophenecarboxylate

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Reaction Steps

A solution of methyl 4-(4-bromo-1-methyl-1H-pyrazol-5-yl)-5-methyl-2-thiophenecarboxylate (300 mg, 0.95 mmol), potassium carbonate (658 mg, 4.76 mmol), bis(tri-t-butylphosphine)palladium(0) (24.32 mg, 0.05 mmol) and 4,4,5,5-tetramethyl-2-(1-methylethenyl)-1,3,2-dioxaborolane (0.18 ml, 0.95 mmol) in 1,4-dioxane (5.3 ml) and H2O (1.0 ml) was stirred at 80° C. in a sealed tube for 12 h. The reaction contents were partitioned between H2O-DCM and the aqueous phase was washed several times with DCM. The combined organic fractions were dried over Na2SO4, concentrated and purified via column chromatography (10-50% EtOAc in hexanes) affording methyl 5-methyl-4-[1-methyl-4-(1-methylethenyl)-1H-pyrazol-5-yl]-2-thiophenecarboxylate (171 mg, 0.58 mmol, 61% yield) as a yellow oil: LCMS (ES) m/z=276 (M+H)+.

Provenance & Evidence