Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is an important regulatory factor in the necroptosis signaling pathway, and is considered an attractive therapeutic target for treating multiple inflammatory diseases. Herein, we describe the design, synthesis, and structure–activity relationships of 4-amino-1,6-dihydro-7H-pyrrolo [2,3-d]pyridazin-7-one derivatives as RIPK1 inhibitors. Among them, 13c showed favorable RIPK1 kinase inhibition activity with an IC₅₀ value of 59.8 nM, and high RIPK1 binding affinity compared with other regulatory kinases of necroptosis (RIPK1 K_d = 3.5 nM, RIPK3 K_d = 1700 nM, and MLKL K_d > 30,000 nM). 13c efficiently blocked TNFα-induced necroptosis in both human and murine cells (EC₅₀ = 1.06–4.58 nM), and inhibited TSZ-induced phosphorylation of the RIPK1/RIPK3/MLKL pathway. In liver microsomal assay studies, the clearance rate and half-life of 13c were 18.40 mL/min/g and 75.33 min, respectively. 13c displayed acceptable pharmacokinetic characteristics, with oral bioavailability of 59.55%. In TNFα-induced systemic inflammatory response syndrome, pretreatment with 13c could effectively protect mice from loss of body temperature and death. Overall, these compounds are promising candidates for future optimization studies.

受体相互作用丝氨酸/苏氨酸蛋白激酶1（RIPK1）是坏死性凋亡信号通路中的重要调节因子，被认为是治疗多种炎症性疾病的有吸引力的治疗靶点。在此，我们描述了作为 RIPK1 抑制剂的 4-amino-1,6-dihydro-7 H -pyrrolo [2,3- d ]pyridazin-7-one 衍生物的设计、合成和构效关系。其中， 13c表现出良好的RIPK1激酶抑制活性，IC ₅₀值为59.8 nM，与其他坏死性凋亡调节激酶相比具有较高的RIPK1结合亲和力（RIPK1 K _d  = 3.5 nM，RIPK3 K _d  = 1700 nM，MLKL K _d）  > 30,000 nm）。13c有效阻断人和小鼠细胞中 TNFα 诱导的坏死性凋亡 (EC ₅₀  = 1.06–4.58 nM)，并抑制 TSZ 诱导的 RIPK1/RIPK3/MLKL 通路磷酸化。在肝微粒体测定研究中， 13c的清除率和半衰期分别为18.40 mL/min/g和75.33 min。13c表现出可接受的药代动力学特征，口服生物利用度为59.55%。在TNFα诱导的全身炎症反应综合征中， 13c预处理可以有效保护小鼠免于体温下降和死亡。总体而言，这些化合物是未来优化研究的有前途的候选化合物。