Discovery of a selective and potent inhibitor of c-Jun N-terminal kinase 1 with anti-pulmonary fibrosis effect.

We synthesized and evaluated a series of derivatives based on the pyrimidine-2,4-diamine scaffold as potential JNK1 inhibitors, incorporating bridging rings and spirocyclic modifications to enhance their inhibitory activity. These compounds were biologically assessed through JNK enzyme inhibition assays and Western Blot analysis. Compounds 13, 14 and 19 demonstrated significant inhibitory activity at both the enzyme and cellular level compared to the lead compound 1 and clinical candidate CC-90001. Notably, 14 exhibited strong inhibitory potency against JNK1 with sub-nanomolar efficacy and suppresses TGF-β-induced epithelial-mesenchymal transition, indicating its potential as a promising candidate for further development as an anti-pulmonary fibrosis agent targeting JNK1.