Bruton's tyrosine kinase (Btk) is a Tec family kinase with a well-defined role in the B cell receptor (BCR) and Fcγ receptor (FcR) signaling pathways, which makes it a uniquely attractive target for the treatment of autoimmune diseases, such as rheumatoid arthritis (RA). We reported a series of compounds bearing 7H-pyrrolo [2,3-d]pyrimidin-4-amine scaffold that potently inhibited Btk in vitro. Analysis of the structure-activity relationships (SAR) and drug-like profiles led to the discovery of the optimal compound B16. B16 preferentially inhibited Btk (IC₅₀ = 21.70 ± 0.82 nM) over closely related kinases with moderate selectivity. Cell-based tests also confirmed that B16 significantly inhibited Btk Y223 auto-phosphorylation and PLCγ2 Y1217 phosphorylation. MTT revealed that B16 displayed weak suppression against normal LO2, HEK293 and THP-1 cell lines with IC₅₀ values over 30 μM. Moreover, B16 showed very weak potential to block the hERG channel (IC₅₀ = 11.10 μM) in comparison to ibrutinib (IC₅₀ = 0.97 μM). Owing to its favorable physicochemical properties (ClogP = 2.53, aqueous solubility ≈ 0.1 mg/mL), pharmacokinetic profiles (F = 49.15%, t_1/2 = 7.02 h) and reasonable CYP450 profile, B16 exhibited potent anti-arthritis activity and similar efficacy to ibrutinib in reducing paw thickness in CIA mice. In conclusion, B16 is a potent, selective and durable inhibitor of Btk and has the potential to a safe and efficacious treatment for arthritis.

布鲁顿酪氨酸激酶（Btk）是一种Tec家族激酶，在B细胞受体（BCR）和Fcγ受体（FcR）信号传导途径中具有明确的作用，这使其成为治疗自身免疫性疾病（例如，类风湿关节炎（RA）。我们报道了一系列带有7 H-吡咯并[2,3 - d ]嘧啶-4-胺骨架的化合物，它们在体外有效抑制Btk 。结构-活性关系（SAR）和类药物概况的分析导致最佳化合物B16的发现。 与紧密相关的激酶相比，B16优先抑制Btk（IC ₅₀ = 21.70±0.82 nM），具有中等选择性。基于细胞的测试还证实了B16显着抑制Btk Y223自磷酸化和PLCγ2Y1217磷酸化。MTT显示B16对正常的LO2，HEK293和THP-1细胞系表现出微弱的抑制作用，IC ₅₀值超过30μM。此外， 与依鲁替尼（IC ₅₀  = 0.97μM）相比，B16阻断hERG通道的潜能非常弱（IC ₅₀ = 11.10μM ）。由于其良好的理化特性（ClogP = 2.53，水溶性≈0.1 mg / mL），药代动力学特征（F = 49.15％，t _1/2  = 7.02 h）和合理的CYP450特征，B16在降低CIA小鼠的足爪厚度方面显示出有效的抗关节炎活性，并且具有与依鲁替尼相似的功效。总之，B16是有效，选择性和持久的Btk抑制剂，具有对关节炎进行安全有效治疗的潜力。