Manufacturing Process
Benzaldehyde and hydroxylamine may be reacted, the product chlorinated and
then reacted with cyanamide to give 5-amino-3-phenyl-1,2,4-oxadiazole.
32 grams of 3-phenyl-5-amino-1,2,4-oxadiazole dissolved in about 150 ml of
anhydrous benzene, 7.8 grams of sodium amide are added and the reaction
mixture heated at the boiling point with stirring for 2 hours. A solution of 38.3
grams of dibutylaminoethyl chloride in benzene is then added and the mixture
heated to boiling under reflux for four hours. The sodium chloride is separated
as previously described, the benzene removed by vacuum distillation and 56
grams of 3-phenyl-5-(dibutylaminoethylamino)-1,2,4-oxadiazole is obtained in
the form of an oil which is then converted directly to the crystalline
hydrochloride. This is accomplished by dissolving the oil in ethanol and adding
the stoichiometric equivalent of anhydrous ethyl ether saturated with gaseous
hydrogen chloride. The recrystallized salt is found to have a melting point of
145°C.
