Adrenergic blocking agents

β-Haloalkylamines are a series of sympathetic blocking compounds. Phenoxybenzamine, the only commercially available β-haloalkylamine, goes under the trade name of dibenzyline and has an onset of sympathetic blocking effect of forty-five minutes and lasts for twenty-four to thirty-six hours. It requires a dose of 10-15 mg./kg. in previously anesthetized animals for full blocking effect and obviously its slowness of onset curtails its usefulness. N-Methyl-N-benzyl-β-chloro-β-phenyl-ethylaminehydrochloride also known as BMEA (for benzyl, methyl, phenethyl amine) differs by having an onset of sympathetic blockade of only five minutes and still has a duration in excess of seventeen hours. In addition, it is about ten times as potent as dibenzyline and is devoid of any secondary effects leading to respiratory arrest of the animal that occasionally accompany dibenzyline. The β -haloalkylamines are not only alpha adrenergic receptor blocking agents but also effective blockers of the histamine receptors in the same dosage. Thus, it was with this knowledge that we set out to complete the work of Van Saxton Hubbard, Union College 1967, attempting to create some useful isomers of N-methyl-N-benzyl- β-chloro-β-phenyl-ethylamine-hydrochloride with the hope that their characteristics would be at least as useful in pharmacology as is the mother compound. (l