Ethyl Bromide → 4-(2,5-Difluorobenzoyl)-1-methylpiperidine

Participants

Reaction Steps

To a stirred suspension of Mg (9.62 g, 0.40 moles) in tetrahydrofuran (THF) (45 ml) was added a few ml of bromoethane to initiate the reaction followed by dropwise addition of freshly distilled 4-chloro-N-methylpiperidine (42.3 g, 6.32 moles) in THF (140 ml). The reaction was initiated with a high intensity heat gun and controlled by the rate of addition of the piperidine. After the addition was complete, the reaction was refluxed for 1 hour. Next 2,5-difluorobenzonitrile (48.2 g, 0.318 moles) in THF (20 ml) was added and the reaction was refluxed for an additional 3 hours. The reaction was allowed to stand for 65 hours and was then poured into a solution of NH4Cl/H2O (120 g/400 ml). The mixture was heated on a steam bath for 2 hours, cooled and extracted with ether (500 ml.). Concentration produced an oil (50.6 g) which the product was distilled from (112° C. @ 0.5 mm) to yield 30.4 g (40%) of the product.

Provenance & Evidence