Originator
Priscoline,Ciba,US,1948
Uses
Reactant for synthesis of imidazoline-containing drug
Uses
Tolazoline is used for treating stable forms of pulmonary hypertension in newborns, and in cases
where systemic arterial oxygenation cannot be achieved in the usual manner under careful
observation of professionals.
Definition
ChEBI: A member of the class of imidazoles that is 4,5-dihydro-1H-imidazole substituted by a benzyl group.
Manufacturing Process
The phenyl-acetiminoether hydrochloride of the formula
from 12 parts of benzylcyanide and ethanol and HCl is mixed with 8 parts of
ethylenediamine hydrate which has been diluted with little alcohol, whereby
the crystals go into solution. The whole is then heated on the water-bath until
the ammonia odor has disappeared, cooled, concentrated caustic potash
solution added, and the separated oil extracted with ether. The solution is
dried with potassium carbonate and potassium hydroxide. After evaporation a
pale oil is left which distills at 147°C under a pressure of 9 mm and which
solidifies in the condenser to a white crystalline mass. The yield amounts to
90% of the theory. The hydrochloride melts at 168° to 170°C.
Therapeutic Function
Vasodilator
General Description
2-Benzylimidazoline is an active vasodilator.
Pharmacology
Tolazoline is a weak, reversible α-adrenoblocker that lowers resistance of peripheral blood
vessels and elevates venous capacity. However, it also exhibits β-adrenomimetic activity,
which consists of the stimulation of cardiac work and is manifest as tachycardia, cholinergic activity, which consists of stimulation of the gastrointestinal tract, and histamine-like
activity, which consists of stimulation of gastric secretion.
Safety Profile
Poison by ingestion,intraperitoneal, and intravenous routes. Mutation data reported. When heated to decomposition it emits toxicfumes of NOx.
Synthesis
Tolazoline, 2-benzyl-2-imidazoline (12.2.7), is synthesized by the heterocyclation of the ethyl ester of iminophenzylacetic acid with ethylendiamine (12.2.6), which
forms the desired product (12.2.7) [32¨C35]. The structure of tolazoline is strikingly similar to |á-adrenergic agonists, which are antiedema sympathomimetics.
