Examination of the structure-activity relationships of 2- (phenylpiperazinoalkoxyphenyl) -thiazolidine-3-carbothioamides and the corresponding carboxamides (1) as new cardiotonic agents was extended by the chemical modification of the phenylpiperazino moiety. The 4-phenylpiperidine (13), 4-phenyltetrahydropyridines (17), and related derivatives were prepared from the chlorides (10) through several intermediates (12, 14, and 16) and tested for cardiotonic activity. Generally, both the 4-phenylpiperidine (13) and 4-phenyltetrahydropyridine (17) derivatives exhibited potent positive inotropic activity comparable to that of 1. The N-phenylpiperidines (9) and amide derivatives (22, 25, and 28) exhibited no significant positive inotropy. This is also the case for the phenylpropylamines (29) and the ethylenediamines (30), which are pseudo-ring analogues of 1 with respect to the piperazine moiety. The activity of the homopiperazine derivative (23) was approximately one-thirtieth of that of the corresponding piperazine derivative (1). Thus, the presence of the six-membered, basic azacycloalkane ring (piperidine or piperazine) with a 4-phenyl group at the end of the alkoxy side chain appears to be essential for the appearance of potent positive inotropic activity in this series of compounds.
通过对
苯基
哌嗪分子进行
化学修饰,扩展了作为新型强心剂的 2-(
苯基
哌嗪烷
氧基
苯基)-
噻唑烷-3-
硫代
酰胺和相应羧
酰胺(1)的结构-活性关系研究。从
氯化物(10)通过几个
中间体(12、14 和 16)制备出了
4-苯基哌啶(13)、4-
苯基四
氢吡啶(17)和相关衍
生物,并进行了强心活性测试。一般来说,
4-苯基哌啶(13)和 4-
苯基四
氢吡啶(17)衍
生物都表现出与 1 相似的强效正性肌力活性,而
N-苯基哌啶(9)和
酰胺衍
生物(22、25 和 28)则没有表现出明显的正性肌力活性。
苯基
丙胺(29)和
乙二胺(30)的情况也是如此,它们是 1 的
哌嗪分子的假环类似物。均
哌嗪衍
生物(23)的活性约为相应
哌嗪衍
生物(1)的三十分之一。因此,在这一系列化合物中,烷
氧基侧链末端含有 4-
苯基基团的六元碱性
氮杂环烷环(
哌啶或
哌嗪)似乎是产生强效正性肌力活性的关键。