Cesium carbonate → 6-Chloro-5-(3,3-difluoroazetidin-1-yl)-pyridine-2-carboxylic acid methyl ester

関与物質

反応条件

反応手順

Under a nitrogen atmosphere a mixture of methyl 5-bromo-6-chloro-pyridine-2-carboxylic acid methyl ester (Example 3 a, 2 g, 8 mmol), 3,3-difluoroazetidine hydrochloride (CAN 288315-03-7, 1 g, 8 mmol), tris(dibenzylideneacetone)dipalladium (CAN 51364-51-3, 0.16 g, 0.16 mmol), (R)-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (CAN 76189-55-4, 0.19 g, 0.32 mmol) and cesium carbonate (3.9 g, 12 mmol) in toluene (50 mL) was stirred at 110° C. overnight. After concentration, the residue was partitioned between water (50 mL) and ethyl acetate (40 mL), the aqueous phase was extracted with ethyl acetate (2×40 mL). The combined organic phase was washed with brine (40 mL), dried over anhydrous sodium sulfate, filtered and concentrated to give a residue. The residue was purified by column chromatography (silica gel, 20 g, 10% ethyl acetate in petroleum ether) to give the target compound (0.44 g, 21%) as light-yellow solid; MS (EI): m/e=263.0 [MH+].

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