A new series of cyanoamidines, N-arylalkyl-N'-cyano-3-pyridinecarboxyamidines was synthesized and evaluated for inhibitory effects on 40 mM KCl-induced contraction and norepinephrine (NE)-induced contraction of rat aorta strips. The N-phenethyl cyanoamidine 4c showed potent vasodilatory action. Further in vitro screening program using 4c as a lead compound resulted in the discovery of highly potent N-[2-(2-chlorophenyl)ethyl]-N'-cyano-3-pyridinecarboxamidine (5j). Compound 5j induced the greatest increase in 86Rb+ efflux among cyanoamidine series. Subsequent modification of the pyridine ring of 5j was performed with evaluation for intravenous and oral antihypertensive activities. Introduction of an amino group at the 5-position of the pyridine ring furnished the new potassium channel opener, 5-amino-N-[2-(2-chlorophenyl)ethyl]-N'-cyano-3-pyridinecarboxamidine (9e; KRN4884), which showed highly potent antihypertensive activity and a long duration of antihypertensive action after oral administration. KRN4884 is under further development as an antihypertensive agent.
合成了一系列新的
氰醇胺,N-芳基烷基-N'-
氰基-3-
吡啶甲酰胺,并评估其对40 mM KCl诱导的收缩和
去甲肾上腺素(NE)诱导的收缩对大鼠主动脉条的抑制作用。N-苯乙基
氰醇胺4c表现出强效的血管舒张作用。随后,以4c作为先导化合物的体外筛选程序发现了高度有效的N-[2-(2-
氯苯基)乙基]-N'-
氰基-3-
吡啶甲酰胺(5j)。化合物5j在
氰醇胺系列中诱导了86Rb+外流的最大增加。随后对5j的
吡啶环进行了修饰,并评估其静脉注射和口服降压活性。在
吡啶环的5位引入
氨基,得到新的
钾通道开放剂5-
氨基-N-[2-(2-
氯苯基)乙基]-N'-
氰基-3-
吡啶甲酰胺(9e;KRN4884),其显示出强效的降压活性,并在口服给药后具有较长的降压作用时间。KRN4884正在进一步开发作为降压药。