Potassium Carbonate → 6-Chloro-5-(1,1-dioxido-isothiazolidin-2-yl)-pyridine-2-carboxylic acid methyl ester

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Reaction Steps

Under a nitrogen atmosphere, a solution of 5-bromo-6-chloro-pyridine-2-carboxylic acid methyl ester (Example 9 c, 1 g, 4 mmol), isothiazolidine 1,1-dioxide (730 mg, 06 mmol), copper(I) iodide (150 mg, 0.8 mmol), 1,3-di(pyridin-2-yl)propane-1,3-dione (CAN 10198-89-7, 180 mg, 0.8 mmol) and potassium carbonate (1.1 g, 8 mmol) in DMF (20 mL) was reacted for 24 h at 110° C. The reaction mixture was poured into water, and extracted with ethyl acetate (3×50 mL). The combined organic extracts were washed with water and brine, dried over anhydrous sodium sulfate and evaporated. The residue was purified by column chromatography (silica gel, 4 g, 10% ethyl acetate in petroleum ether) to yield the title compound (0.048 g, 1.6 mmol, 41.4%) as yellow solid; MS (EI): m/e=291.0 [M+H]+.

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