TTK/Mps1 is a key kinase controlling progression of cell division via participation in the mitotic spindle assembly checkpoint and is overexpressed in a number of human cancers. Herein we report the discovery of 4-(4-aminopyrazolo[1,5-a][1,3,5]triazin-8-yl)benzamides as a potent, novel class of TTK inhibitors. The series was identified by means of bioisosteric replacement of the related imidazopyrazine and imidazopyridazine scaffolds. Optimization led to the identification of compounds with excellent potency (K_i = 0.8 nM) and exceptional kinase selectivity. The SAR indicates a strong dependence of activity on the presence of the N-cyclopropyl-2-methylbenzamide moiety delineating the geometry for 1½ type kinase inhibitor. Molecular modeling indicates the extensive and optimal contacts, mediated through H-bonds and hydrophobic interactions, are responsible for the selectivity and potency of the inhibitors. The compounds demonstrate a strong anti-proliferative activity in a panel of human cancer cell lines (HCT116 GI₅₀ <15 nM) and good rodent pharmacokinetics (oral %F 97%).

TTK / Mps1是通过参与有丝分裂纺锤体装配检查点来控制细胞分裂进程的关键激酶，在许多人类癌症中均过表达。在本文中，我们报告了4-（4-氨基吡唑并[1,5- a ] [1,3,5]三嗪-8-基）苯甲酰胺作为一种强力的新型TTK抑制剂的发现。该系列通过相关等价的咪唑并吡嗪和咪唑并哒嗪支架的生物立体置换来鉴定。通过优化，鉴定出具有出色效价（K _i  = 0.8 nM）和出色的激酶选择性的化合物。SAR表示活动强烈依赖于N的存在-环丙基-2-甲基苯甲酰胺部分，描绘了1½型激酶抑制剂的几何形状。分子建模表明，通过氢键和疏水相互作用介导的广泛而最佳的接触是抑制剂的选择性和效力的原因。这些化合物在一组人类癌细胞系（HCT116 GI ₅₀  <15 nM）中显示出强大的抗增殖活性，并具有良好的啮齿动物药代动力学（口服％F 97％）。