Ethyl 4-chlorobenzoate → 2-(4-Bromopyridin-2-yl)-1-(4-chlorophenyl)ethanone

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Under a stream of nitrogen, 5 g (29.07 mmol) of 4-bromo-2-methylpyridine and 11.27 g (61.04 mmol) of ethyl 4-chlorobenzoate are placed in a round-bottomed flask and dissolved in 50 mL of anhydrous tetrahydrofuran. The solution is cooled to 5° C. and 70 mL (70 mmol) of a lithium hexamethyldisilazane solution (1M in tetrahydrofuran) are added dropwise. After addition, the mixture is stirred at room temperature for 2 hours, cooled to 5° C., and 100 mL of water are then gradually added. The medium is then diluted with 250 mL of ethyl acetate and 100 mL of water. The organic phase is separated out and the aqueous phase is extracted twice with 100 mL of ethyl acetate. The organic phases are then combined, dried over sodium sulfate and filtered. 15 g of silica are then added to the filtrate, which is then concentrated under reduced pressure. The powder obtained is used as solid deposit for a chromatography on silica gel, eluting with a mixture of cyclohexane and ethyl acetate (9/1). 8.4 g (93%) of compound are obtained in the faun of a yellow powder.

Herkunft & Nachweise