新型嘧啶单环类非经典叶酸拮抗剂的合成及抗肿瘤活性研究

以课题组前期设计合成的非经典叶酸拮抗剂6-(4'-甲基苯乙基)-N5-氯乙酰基-2,4-二氨基哌啶并3,2-d]嘧啶(wm-8.2)为先导化合物,将wm-8.2中的哌啶并嘧啶双环结构简化为嘧啶单环结构,以提高分子柔韧性并简化分子结构,根据6-位空间占位设计6-H和6-甲基两个系列,考察了不同桥链长度和不同芳香杂环侧链对抗肿瘤活性的影响.同时对具有叶酸抑制剂分子结构特征的关键中间体进行活性对比测定,研究了N(5)位氯乙酰基对活性的影响.两个系列目标化合物和关键中间体共36个化合物的结构均经1H NMR,13C NMR和MS确证.生物活性测定表明,6位为甲基的化合物中,具有三碳桥链及对甲基苯环侧链的6-甲基-2,4-二氨基-5-(N-(4-甲基苯基)丙基-N-(2-氯乙酰基))氨基嘧啶(6b-3)具有最好的HL-60、A549和HCT116细胞增殖抑制活性,IC50分别为0.25,0.83和0.63μmol?L^-1.化合物6b-3在N(5)位氯乙酰基取代之前的关键中间体6-甲基-2,4-二氨基-5-(N-(4-甲基苯基)丙基)氨基嘧啶(5b-3)具有最优的二氢叶酸还原酶抑制活性.总结了化合物的构效关系,并用计算机模拟进行了阐释.

Synthesis and Antitumor Activity of Novel Pyrimidine Monocyclic Nonclassical Antifolates

Regarding the nonclassical antifolates 6-(4'-methylphenethyl)-5-chloroacetyl-5,6,7,8-tetrahydropyrido3,2-d]pyrimidine(wm-8.2)as the lead compound,in order to improve molecular flexibility and simplify molecular structure,two series of compounds were designed and synthesized according to the 6-H and 6-methyl group.And the effects of carbon chain length and aromatic heterocyclic side chain on antitumor activity were investgated.Besides,the activities of key intermediates with molecular skeleton of folic acid inhibitor were measured to study the effect of the chloroacetyl group at N(5)position.Structures of 36 target compounds and key intermediates were confirmed by 1H NMR,13C NMR and MS.The biological activity results showed that 6-methyl-2,4-diamino-5-(N-(4-methylphenyl)propyl-N-(2-chloroacetyl))aminopyrimidine(6b-3),which had three-carbon bridge and p-methylbenzene ring side chain,exhibited the best inhibition activities against HL-60,A549 and HCT116 cells with IC50 values as 0.25,0.83 and 0.63μmol?L-1 respectively.6-Methyl-2,4-diamino-5-(N-(4-methylphenyl)-propyl)aminopyrimidine(5b-3),the key intermediate of 6b-3,showed excellent dihydrofolate reductase inhibitory activity.Molecular docking studies further explored the structure-activity relationship and possible causes of the difference inhibitory activity against dihydrofolate reductase.