Cyanoamidines. I. Synthesis and Vasodilatory Activity of N-Substituted Heteroaromatic Cyanoamidines

Abstract

Various heteroaromatic cyanoamidines were synthesized starting from nitriles via cyanoimidates or from amides via thioamides. The compounds were tested for inhibitory effect on the 40 mM K⁺-induced contraction of rat aorta strips and selected compounds were also evaluated for antagonism of the norepinephrine-induced contraction. Most of the cyanoamidines showed vasodilatory activities. Potent vasoactive compounds were also examined for stimulation of the ⁸⁶Rb⁺ efflux to determine their potassium channel opening actions. Maximum potency was displayed by N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboxyamidine (3h). The methanesulfonate of 3h, which was designated as KRN2391, has been selected for further development as an antianginal agent.