Organic Syntheses, Coll. Vol. 5, p.816 (1973); Vol. 40, p.74 (1960).
A dry 1-l. three-necked round-bottomed flask is fitted in the center neck with a sweep-blade stirrer whose shaft passes through an airtight bearing (Note 1)
. One side neck is fitted with a condenser topped by a soda-lime drying tube
, and the other is fitted with a solid stopper
. In the flask are placed 75 ml. of piperidine (Note 2)
and 15.6 g. (0.4 mole) of sodium amide (Note 3)
, and the mixture is heated at reflux (Note 4)
for 15 minutes with good stirring. The mixture is cooled just below reflux temperature, and 46 g. (0.2 mole) of sodium β-naphthalenesulfonate (Note 5)
is added, followed by an additional 75 ml. of piperidine
. The mixture is then heated at reflux for 12 hours with stirring.
To the cooled reaction mixture, 200 ml. of water is added carefully with stirring. Potassium carbonate
is added with continued stirring until the water layer is saturated; the mixture is now transferred to a separatory funnel
and extracted three times with 60-ml. portions of ether
. The combined ether
extracts are dried over solid sodium hydroxide
and are then transferred to a simple distillation apparatus
. Distillation is commenced with a steam bath
as source of heat; when most of the ether
has been removed, the steam bath is replaced by a flame. Distillation is continued until most of the piperidine
) has been removed. The cooled residue in the distillation flask is recrystallized from petroleum ether (boiling range 30–60°)
with the use of charcoal. There is obtained 30.0 g.
) of N-β-naphthylpiperidine
as tan crystals, m.p. 52–56°
. An additional recrystallization from the same solvent gives crystals, m.p. 56–58°
, with about 10% loss in weight (Note 6)
The submitters used a ball-joint bearing
. A mercury seal or a Trubore bearing
should also suffice.
was purified by 6 hours' refluxing with sodium
metal followed by distillation from sodium
Sodium amide from Farchan Research Laboratories, Cleveland, Ohio
, was used.
The submitters used an electric heating mantle
as a source of heat.
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