A mixture of 26.1 g of o-benzylphenoxy-β-chloropropane and 17 g of
piperidine is refluxed over a period of 32 hours until the temperature is about
124°C and a nearly solid mixture is formed due to the precipitation of a salt.
The mixture is then refluxed over a period of 48 hours at about 160°C and
the reaction product obtained is cooled and dissolved in methanol. The
solution is concentrated under reduced pressure to yield an oil which is added to 200 ml 3N hydrochloric acid whereupon the mixture is shaken with ether, 3
x 100 ml, until the aqueous phase is clear. The ether solution is washed with
water, 3 x 50 ml, and the water present in the combined aqueous phase and
water used for washing is evaporated under reduced pressure methanol being
added three times when the residue appears to be dry. The impure
hydrochloride of o-benzylphenoxy-β-N-piperidinopropane, 41 g, obtained is
dissolved in 100 ml water and 100 ml 30% aqueous sodium hydroxide
solution are added, whereupon precipitated oil is extracted with ether, 1 x 100
and 2 x 50 ml. The ether solution is washed with water, 4 x 50 ml, dried with
magnesium sulfate and the ether is removed under reduced pressure. The
residue, 25.2 g, is distilled under reduced pressure and the main fraction,
23.2 g, BP 159°-161°C/0.2 mm.
