A series of novel 5-methylpyrazolo[1,5-a]pyrimidine derivatives (10a–10x) were designed, synthesized, and evaluated for their in vitro inhibitory activities against c-Met kinase and antiproliferative activities against the SH-SY5Y, MDA-MB-231, A549, and HepG2 cell lines. Most of the compounds remarkably inhibited c-Met kinase and showed moderate to good cytotoxicity and selectivity toward the four cancer cell lines. Among them, compounds 10b and 10f were the two most potent selective c-Met inhibitors with half-maximal inhibitory concentration (IC₅₀) values of 5.17±0.48 nM and 5.62±0.78 nM, respectively, and suppression abilities comparable with the positive control cabozantinib. Cell proliferation assay further demonstrated that the two most promising compounds 10a and 10b also showed good cytotoxicity and selectivity toward MDA-MB-231 cells, with IC₅₀ values of 26.67±2.56 μM and 26.83±2.41 μM, respectively. Compounds 10f and 10g showed cytotoxicity and selectivity toward A549 cells, with IC₅₀ values of 20.20±2.04 μM and 21.65±1.58 μM, respectively. All antiproliferative activities were within the range of those of cabozantinib. Notably, these compounds presented relatively low hepatotoxicity compared with reference drugs. Moreover, the preliminary structure-activity relationship and docking studies revealed that replacement of a nitrogen-containing heterocycle on the R₂ (block A) group might improve the c-Met kinase inhibitory and antiproliferative effects in MDA-MB-231 cells, whereas displacement by a substituted benzene ring, especially for the p-fluorophenyl or 4-fluoro-3-methoxyphenyl moiety, on the R₂ group enhanced cytotoxicity toward A549 cells. Together, these results suggest that 10b and 10f are promising compounds and provide a basis for their development as new antitumor agents.

设计，合成了一系列新颖的5-甲基吡唑并[1,5-a]嘧啶衍生物（10a-10x），并评估了其对c-Met激酶的体外抑制活性以及对SH-SY5Y，MDA-的抗增殖活性。 MB-231，A549和HepG2细胞系。大多数化合物显着抑制c-Met激酶，并显示出对四种癌细胞的中等至良好的细胞毒性和选择性。其中，化合物10b和10f是两种最有效的选择性c-Met抑制剂，抑制浓度最高一半（IC ₅₀）值分别为5.17±0.48 nM和5.62±0.78 nM，其抑制能力与阳性对照卡博替尼相当。细胞增殖试验进一步证明，两种最有希望的化合物10a和10b对MDA-MB-231细胞也显示出良好的细胞毒性和选择性，IC ₅₀值分别为26.67±2.56μM和26.83±2.41μM。化合物10f和10g对A549细胞具有细胞毒性和选择性，IC ₅₀分别为20.20±2.04μM和21.65±1.58μM。所有抗增殖活性均在卡博替尼的范围内。值得注意的是，与参考药物相比，这些化合物具有较低的肝毒性。此外，初步的结构-活性关系和对接研究表明，在R ₂（嵌段A）基团上取代含氮杂环可能会改善MDA-MB-231细胞中c-Met激酶的抑制和抗增殖作用，而置换R ₂基团上的被取代的苯环，特别是对氟苯基或4-氟-3-甲氧基苯基部分的苯环，增强了对A549细胞的细胞毒性。这些结果加在一起表明10b和10f 是有前途的化合物，并为它们作为新的抗肿瘤药的发展提供了基础。