ATR kinase is essential to the viability of replicating cells responding to the accumulation of single-strand breaks in DNA, which is an attractive anticancer drug target based on synthetic lethality. Herein we design, synthesize, and evaluate a novel series of fused pyrimidine derivatives as ATR inhibitors. As a result, compound 48f, with an IC₅₀ value of 0.0030 μM against ATR, displayed strong monotherapy efficacy in ataxia-telangiectasia mutated (ATM) kinase-deficient tumor cells LoVo, SW620, OVCAR-3 cell lines with IC₅₀ values of 0.040 μM, 0.095 μM, 0.098 μM, respectively. More importantly, the combination of 48f with AZD-1390, cisplatin, oxaliplatin, and olaparib respectively resulted in synergistic activity against HT-29, HCT116, A549, MCF-7, MDA-MB-231 cells. Moreover, 48f showed a favorable pharmacokinetic profile with a bioavailability of 30.0% in SD rats, acceptable PPB, high permeability (P_app A to B = 8.23 cm s⁻¹ × 10⁻⁶), and low risk of drug-drug interactions. Collectively, compound 48f could be a promising compound for further investigation.

ATR 激酶对于响应 DNA 中单链断裂积累的复制细胞的活力至关重要，这是一种基于合成致死性的有吸引力的抗癌药物靶标。在此，我们设计、合成和评估了一系列新型稠合嘧啶衍生物作为 ATR 抑制剂。结果，针对 ATR的 IC ₅₀值为 0.0030 μM的化合物48f在共济失调-毛细血管扩张症突变 (ATM) 激酶缺陷型肿瘤细胞 LoVo、SW620、OVCAR-3 细胞系中显示出强大的单一疗法功效，IC ₅₀值为 0.040分别为 μM、0.095 μM、0.098 μM。更重要的是，48f与AZD-1390、顺铂、奥沙利铂联合使用和olaparib分别对 HT-29、HCT116、A549、MCF-7、MDA-MB-231 细胞产生协同活性。此外，48f显示出良好的药代动力学特征，在 SD 大鼠中的生物利用度为 30.0%、可接受的 PPB、高渗透性（P _app A 至 B = 8.23 cm s ^-1  × 10 ^-6）以及药物-药物相互作用的低风险。总的来说，化合物48f可能是一种有希望进行进一步研究的化合物。