Potassium Carbonate → Methyl 2-chloro-6-phenylpyridine-3-carboxylate

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Reaction Steps

To the mixture of 2,6-dichloro-nicotinic acid methyl ester (4.0 g, 19 mmol) synthesized in Example 23 and tetrahydrofuran (39 ml), phenyl boronic acid (2.5 g, 19 mmol), potassium carbonate (8.0 g, 58 mmol), and tetrakis(triphenylphosphine)palladium(0) (1.2 g, 0.97 mmol) were added, and the obtained reaction mixture was stirred for 16 hours while being heated to reflux. The reaction mixture was cooled to room temperature, and then insoluble matter was removed by filtration. The solvents were evaporated under reduced pressure from the filtrate, and then water and ethyl acetate were added to the obtained residue, followed by extraction. The organic layer and the aqueous layer were separated, and the aqueous layer was further extracted using ethyl acetate. The organic layers were mixed, washed with saturated saline, and dried using anhydrous sodium sulfate. The solvents were evaporated under reduced pressure, and the obtained residue was purified with silica gel column chromatography (heptane:ethyl acetate=10:1 to 3:1). The obtained crude compound was recrystallized using the mixed solvent of heptane-diethyl ether, thereby obtaining the entitled compound (2.2 g, 47%).

Provenance & Evidence