synthesized. The total synthesis of each isomeric fused heterocycle through multistep heterocyclization was followed by glycosylation and derivatization at position 4 by cross‐coupling reactions or nucleophilic substitutions. All compounds were tested for cytostatic and antiviral activity. The most active were pyrido[4′,3′:4,5]pyrimidine nucleosides bearing MeO, NH2, MeS, or CH3 groups at position 4, which
设计并合成了在不同位置具有
吡啶氮原子的新颖的4个取代的
吡啶基融合的7个氮杂
嘌呤核糖核苷的所有四个异构体系列。通过多步杂环化,每个异构体稠合杂环的总合成,然后通过交叉偶联反应或亲核取代在位置4进行糖基化和衍生化。测试所有化合物的细胞抑制活性和抗病毒活性。活性最高的是带有MeO,NH 2,MeS或CH 3的
吡啶并[4',3':4,5]
嘧啶核苷在位置4的基团中,它们显示出亚微摩尔的细胞毒性作用和对癌细胞的良好选择性。该机制涉及通过
磷酸化激活并掺入DNA,其中修饰的
核糖核苷的存在导致双链断裂和凋亡。