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

Participants

Reaction Conditions

Reaction Steps

To a 300 mL sealed flask was added 1-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (8.14 g, 39.1 mmol), potassium carbonate (12.98 g, 94 mmol), methyl 4-bromo-5-chloro-2-thiophenecarboxylate (8 g, 31.3 mmol) and bis(tri-t-butylphosphine)palladium(0) (0.40 g, 0.78 mmol) in 1,4-dioxane (50 ml) and H2O (6 ml). After stirring for 90 min at 75° C., the reaction solution was diluted with DCM (100 mL) and washed with H2O. The organic layer was dried Na2SO4, filtered and concentrated. The reaction residue was purified on silica gel [hexanes/EtOAc, 2:1] to give the product [5.7 g, 70%] as a tan solid: LCMS (ES) m/z 258 (M+H)+.

Provenance & Evidence