Abstract
Piperidine, one of alicyclic amines, shows not only nicotine-like synaptotropic actions but also a marked respiratory stimulant action due to the chemoreflex of carotid body. Accordingly, in expectation of preparing some potent respiratory stimulants, two series of compounds were synthesized by the substitution of the pyridine ring in the nikethamide structure for a piperidine ring and the substitution of morpholino groups in the dimorpholamine (dim.) for two piperidino groups or similar piperidine ones. Among them, N, N'- dibutyl-N, N'-bis (piperidinocarbonyl) ethylenediamine (VII) was the most potent in respiratory stimulant action.
In rabbits, the respiratory stimulant action of VII was 4 to 5 times as potent as that of dim. and the duration of the effect was twice as long as that of dim. Its toxicity in mice was about a half that of dim. Furthermore, the significance of the role of piperidino group in manifestation of pharmacological activities was demonstrated.
