Cyanoguanidine-thiourea equivalence in the development of the histamine H2-receptor antagonist, cimetidine
作者:G. J. Durant、J. C. Emmett、C. R. Ganellin、P. D. Miles、M. E. Parsons、H. D. Prain、G. R. White
DOI:10.1021/jm00217a007
日期:1977.7
which are antagonists of decreased potency. The guanidine is very basic and at physiological pH is completely protonated. However, introduction of strongly electronegative substituents into the guanidine group reduces basicity and gives potent H2-receptor antagonists, viz. the cyanoguanidine 2b (cimetidine, "Tagamet") and nitroguanidine 2e. A correspondence between the activity of thioureas and cyanoguanidines
在组胺H 2受体拮抗剂甲酰胺(2a)中,用羰基氧(= O)或亚氨基氮(= NH)等位取代硫酮硫(= S),得到脲2c和胍2d,它们是效力降低的拮抗剂。胍是非常碱性的并且在生理pH下完全质子化。但是,将强电负性取代基引入胍基会降低碱性,并产生有效的H2受体拮抗剂。氰基胍2b(西咪替丁,“塔加美特”)和硝基胍2e。对于一系列结构1-4,证明了硫脲和氰基胍活性之间的对应关系。氰基胍和硫脲在许多物理化学性质上的密切对应关系以及H2-受体拮抗剂中这些基团的药理学等效性导致人们将氰基胍和硫脲描述为生物等排体。氰基胍2b的酸水解在环境温度下产生氨基甲酰基胍2f,在升高的温度下产生胍2d。在体内,西咪替丁作为组胺刺激的胃酸分泌的抑制剂,其活性比甲乙酰胺稍强,并在临床上用于治疗消化性溃疡和相关的胃肠道疾病。