Diethyl Ether → 1,4-Dibenzyl-4-cyanopiperidine

Participants

Reaction Conditions

Reaction Steps

A solution of 15 g of 4-cyanopiperidine in 250 ml of THF is cooled to -50° C., 190 ml of a 1.5M solution of lithium diisopropylamide in cyclohexane is added dropwise and the mixture is left stirring for 30 minutes at -50° C. 34 ml of benzylbromide are then added slowly and the mixture is left stirring for 3 hours while allowing the temperature to rise to RT. The reaction mixture is poured into an ice/concentrated HCl mixture, ether is added and the precipitate formed is drained and washed with water. The precipitate is taken up in water, the mixture is alkalinized to pH 12 by adding concentrated NaOH solution and extracted with ether, the organic phase is dried over MgSO4 and the solvent is evaporated off under vacuum. 31.7 g of the expected product are obtained after crystallization in pentane, m.p.=92° C.

Provenance & Evidence