Combinatorial and in situ Approachies to Lead and Refined Compounds

在之前的资助期间，第一个GABAB受体的小分子正向调节器被发现，正向调节被发现是一种可行的策略，可以在动物模型中逆转与尼古丁依赖相关的行为，同时将不良副作用降至最低。通过这一应用，我们寻求继续开发GABA{B}受体正向调节剂的资源，并了解更多关于它们的作用机制。项目1的目标是完成现有的基于嘧啶的化合物的提纯，并找到具有更好性能的替代结构。由一名 通过详细的构效关系研究，建议在保持亲和力的同时，对嘧啶结构的某些关键位置进行修饰以增加溶解度。我们还将开展一项平行努力，通过用显示类似取向的官能团的杂环取代中心的嘧啶环来生成新的铅结构。在所有情况下，合成路线都是短的、高产量的，并且可以容忍不同的官能团，以使优化铅结构变得容易。此外，还将探索另外两条发现路线。第一个利用了佛罗里达州斯克里普斯的大型化合物集合，将通过对项目2中成功的正调节器结构的相似性建模来挖掘这些化合物。将筛选得到的候选化合物，并将新的线索纳入项目1的合成和测试周期。此外，我们将使用靶向合成技术将该计划中已经开发的正调节剂转化为GABA{B}受体的两个结合位点。这种方法使用高度选择性的连接反应来连接小分子，只有在同时结合到目标蛋白质上的相邻位置时才能连接，从而产生高亲和力和选择性的二价配体。所有新化合物将通过芬兰实验室的受体结合分析以及项目2中的第二信使和信号分析进行筛选。通过与项目2的体外测试、体内药理学和生物信息学功能的密切合作，最佳化合物将被识别和提炼，以达到项目3中尼古丁依赖动物模型行为研究的优化结构。

In the previous funding period, the first small-molecule positive modulators of the GABAB receptor were discovered, and positive modulation was found to be a viable strategy for reversing behaviors with relevance to nicotine dependence in animal models, while minimizing undesired side-effects. With this application, we seek the resources to continue the development of GABA{B} receptor positive modulators and learn more about their mechanism of action. The goals of Project 1 are to complete the refinement of the existing pyrimidine-based compounds and to find alternative structures with even better properties. Guided by a detailed structure-activity study, modifications certain key positions of the pyrimidine structure are proposed to increase solubility while retaining affinity. We will also mount a parallel effort to generate new lead structures by replacing the central pyrimidine ring with heterocycles that display functional groups in similar orientations. In all cases, the synthetic routes are short, high-yielding, and tolerant of diverse functionality, in order to make it easy to optimize lead structures. Two additional lines of discovery will also be pursued. The first takes advantage of the large compound collection at Scripps Florida, which will be mined by similarity modeling to successful positive modulator structures in Project 2. The resulting candidates will be screened and new leads will be incorporated into the synthesis and testing cycle of Project 1. In addition, we will employ the technique of target-guided synthesis to convert the positive modulators already developed in this program into two-site binders to the GABA{B} receptor. This approach uses a highly selective connecting reaction to join small molecules only when simultaneously bound to adjacent sites on the target protein, giving rise to bivalent ligands of high affinity and selectivity. All new compounds will be screened by a receptor binding assay in the Finn laboratory and by second messenger and signaling assays in Project 2. By close collaboration with the in vitro testing, in vivo pharmacology, and bioinformatics capabilities of Project 2, the best compounds will be identified and refined to arrive at optimized structures for behavioral studies in animal models of nicotine dependence in Project 3.