Cyclin D dependent kinases (CDK4 and CDK6) regulate entry into S phase of the cell cycle and are validated targets for anticancer drug discovery. Herein we detail the discovery of a novel series of 4-thiazol-N-(pyridin-2-yl)pyrimidin-2-amine derivatives as highly potent and selective inhibitors of CDK4 and CDK6. Medicinal chemistry optimization resulted in 83, an orally bioavailable inhibitor molecule with remarkable selectivity. Repeated oral administration of 83 caused marked inhibition of tumor growth in MV4-11 acute myeloid leukemia mouse xenografts without having a negative effect on body weight and showing any sign of clinical toxicity. The data merit 83 as a clinical development candidate.

中文翻译：

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高效，选择性和口服生物利用度的4-噻唑-N-（吡啶-2-基）嘧啶-2-胺细胞周期蛋白依赖性激酶4和6抑制剂作为抗癌候选药物：设计，合成和评估

依赖细胞周期蛋白D的激酶（CDK4和CDK6）调节细胞周期进入S期的进入，并且是抗癌药物发现的有效靶点。本文中，我们详细介绍了一系列新型的4-噻唑-N-（吡啶-2-基）嘧啶-2-胺衍生物，它们是CDK4和CDK6的高效抑制剂。药物化学优化产生了83种具有选择性的口服生物利用抑制剂分子。重复口服83可以明显抑制MV4-11急性骨髓性白血病小鼠异种移植物中的肿瘤生长，而对体重没有负面影响，并且没有任何临床毒性迹象。数据值得83作为临床开发候选者。