Anzini Maurizio, Canullo Laura, Braile Carlo, Cappelli Andrea, Gallelli Andrea, Vomero Salvatore, Menziani M Cristina, De Benedetti Pier G, Rizzo Milena, Collina Simona, Azzolina Ornella, Sbacchi Massimo, Ghelardini Carla, Galeotti Nicoletta
Dipartimento Farmaco Chimico Tecnologico, Università degli Studi di Siena, Via A. Moro, 53100 Siena, Italy.
J Med Chem. 2003 Aug 28;46(18):3853-64. doi: 10.1021/jm0307640.
The synthesis and biological evaluation of a series of new derivatives of 2-substituted 5-phenyl-1,4-benzodiazepines, structurally related to tifluadom (5), are reported. Chemical and pharmacological studies on compounds 6 have been pursued with the aim of expanding the SAR data and validating the previously proposed model of interaction of this class of compounds with the kappa-opioid receptor. The synthesis of the previously described compounds 6 has been reinvestigated in order to obtain a more direct synthetic procedure. To study the relationship between the stereochemistry and the receptor binding affinity, compounds 6e and 6k were selected on the basis of their evident structural resemblance to tifluadom. Since a different specificity of action could be expected for the enantiomers of 6e and 6k, owing to the results shown by (S)- and (R)-tifluadom, their racemic mixtures have been resolved by means of liquid chromatography with chiral stationary phases (CSP), and the absolute configuration of the enantiomers has been studied by circular dichroism (CD) and (1)H NMR techniques. Moreover, some new 2-[(acylamino)ethyl]-1,4-benzodiazepine derivatives, 6a-d,f,g,j, have been synthesized, while the whole series (6a-o) has been tested for its potential affinity toward human cloned kappa-opioid receptor. The most impressive result obtained from the binding studies lies in the fact that this series of 2-[2-(acylamino)ethyl]-1,4-benzodiazepine derivatives binds the human cloned kappa-opioid receptor subtype very tightly. Indeed, almost all the ligands within this class show subnanomolar K(i) values, and the least potent compound 6o shows, in any case, an affinity in the nanomolar range. A comparison of the affinities obtained in human cloned kappa-receptor with the correspondent one obtained in native guinea pig kappa-receptor suggests that the human cloned kappa-receptor is less effective in discriminating the substitution pattern than the native guinea pig kappa-receptor. Furthermore, the results obtained are discussed with respect to the interaction with the homology model of the human kappa-opioid receptor, built on the recently solved crystal structure of rhodopsin. Finally, the potential antinociceptive and antiamnesic properties of compounds 6e and 6i have been investigated by means of the hot-plate and passive avoidance test in mice, respectively.
本文报道了一系列与替氟朵（5）结构相关的2-取代-5-苯基-1,4-苯二氮䓬新衍生物的合成及生物学评价。对化合物6进行了化学和药理学研究，旨在扩展构效关系（SAR）数据，并验证此前提出的这类化合物与κ-阿片受体相互作用的模型。为了获得更直接的合成方法，对之前描述的化合物6的合成进行了重新研究。为了研究立体化学与受体结合亲和力之间的关系，基于化合物6e和6k与替氟朵明显的结构相似性对其进行了选择。由于（S）-和（R）-替氟朵的结果表明，预计6e和6k的对映体具有不同的作用特异性，因此通过手性固定相（CSP）液相色谱法拆分了它们的外消旋混合物，并通过圆二色性（CD）和（1）H NMR技术研究了对映体的绝对构型。此外，还合成了一些新的2-[(酰氨基)乙基]-1,4-苯二氮䓬衍生物6a-d、f、g、j，同时对整个系列（6a-o）进行了对人克隆κ-阿片受体潜在亲和力的测试。结合研究得到的最令人印象深刻的结果是，这一系列2-[2-(酰氨基)乙基]-1,4-苯二氮䓬衍生物与人克隆κ-阿片受体亚型结合非常紧密。实际上，这类化合物中的几乎所有配体都显示出亚纳摩尔的K(i)值，并且在任何情况下，活性最低的化合物6o也显示出纳摩尔范围内的亲和力。将在人克隆κ-受体中获得的亲和力与在天然豚鼠κ-受体中获得的相应亲和力进行比较表明，人克隆κ-受体在区分取代模式方面不如天然豚鼠κ-受体有效。此外，根据与基于最近解析的视紫红质晶体结构构建的人κ-阿片受体同源模型的相互作用对所得结果进行了讨论。最后，分别通过小鼠热板试验和被动回避试验研究了化合物6e和6i的潜在镇痛和抗遗忘特性。
