Potassium Carbonate → methyl 5-ethyl-4-(1-methyl-1H-pyrazol-5-yl)-2-furancarboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of methyl 4-bromo-5-ethyl-2-furancarboxylate (1.1 g, 4.72 mmol), potassium carbonate (3.26 g, 23.60 mmol), 1-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (1.178 g, 5.66 mmol)[prepared according to Preparation 7] and bis(tri-t-butylphosphine)palladium(0) (0.121 g, 0.24 mmol) were combined in a sealed tube and stirred at 80° C. for 1 h. LCMS showed 4:1 pdt/sm. Additional 1-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (1.178 g, 5.66 mmol) and bis(tri-t-butylphosphine)palladium(0) (0.121 g, 0.24 mmol) were added and the solution stirred an additional 2 h where crude LCMS showed nearly complete conversion to product. The reaction contents were then 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-ethyl-4-(1-methyl-1H-pyrazol-5-yl)-2-furancarboxylate (950 mg, 3.37 mmol, 71.3% yield) as a yellow oil: LCMS (ES) m/e 235 (M+H)+.

Provenance & Evidence