Stigmonene,Warner Lambert,US,1949
56 grams of dimethylcarbamyl chloride were gradually added over a period of
50 minutes to a solution of 45 grams of 3-pyridol in a mixture of 300 cc of
benzene and 69 grams of triethylamine. The reaction mass was then agitated
at 80°C for 3 hours and permitted to cool. The triethylamine hydrochloride
was removed by filtration and solvents distilled from the filtrate under vacuum
in a nitrogen atmosphere. The residual oil was then fractionated under
vacuum whereby, after removal of unchanged dimethylcarbamyl chloride, a
product distilling at 90°C at 0.3 mm was obtained; this product was the
dimethylcarbamyl ester of 3-pyridol.
60 grams of the ester prepared as above described were dissolved in 225 cc
of benzene and 92.5 grams of benzyl bromide were added thereto. The
solution was stirred at room temperature for 24 hours and refluxed for 3
additional hours. At the end of this time the crude product which formed was
separated, washed with benzene and dissolved in water. The aqueous solution
was extracted with ether, filtered through charcoal and then evaporated to
dryness in a nitrogen atmosphere; traces of water were removed by
redissolving the oily residue in absolute alcohol, adding benzene and then
evaporating the mixture to dryness under vacuum. The yellow oil thus
obtained was then dissolved in a mixture of 300 cc of benzene and 55 cc of
absolute alcohol under reflux, the solution cooled, and 340 cc of absolute
ether added. The solution was then seeded and maintained at 5°C for two
days. The crystalline product obtained was filtered and dried, a product
melting between 115°C and 116°C being obtained. This product was the
desired 1 benzyl-3-(dimethylcarbamyloxy)-pyridinium bromide.
