2,5-Dibromopyridine → (2R)-1-(5-bromopyridin-2-yl)-2-((tetrahydro-2H-pyran-2-yl)oxy)propan-1-one

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Reaction Steps

2,5-dibromopyridine (5 g, 21.1 mmol) was dissolved in dried toluene (100 mL), cooled to −78° C., to which n-butyl lithium (9 mL, 22.5 mmol, 2.5 M solution in n-hexane) was added dropwise. The mixture was allowed to react at −78° C. for 2 hrs, and then the solution of (2R)-1-morpholino-2-((tetrahydro-2H-pyran-2-yl)oxy)propan-1-one (7.7 g, 31.6 mmol) in toluene was added dropwise and allowed to react at −78° C. for 5 hrs. The reaction was monitored by TLC (petroleum ether). After the reaction completed, the reaction was quenched by adding saturated solution of ammonium chloride. The mixture was raised to room temperature and diluted with water. The toluene layer was separated and extracted with ethyl acetate. The organic phase was combined, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, and then dried by rotary dryer. Column chromatography (petroleum ether) afforded 4.1 g of pale yellow solid (compound 1a), yield 62%.

Provenance & Evidence