Meier C, Lorey M, De Clercq E, Balzarini J
Institute of Organic Chemistry, Julius-Maximilians-University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
J Med Chem. 1998 Apr 23;41(9):1417-27. doi: 10.1021/jm970664s.
The synthesis, hydrolysis, and antiviral evaluation of novel, lipophilic cycloSal-d4TMP derivatives 3a-h of the anti-HIV dideoxynucleoside 2',3'-dideoxy-2',3'-didehydrothymidine (d4T, 1) are reported. This pro-nucleotide concept has been designed to deliver d4TMP (2) by selective chemical hydrolysis. All compounds 3a-h were synthesized using phosphorus(III) chemistry in good yields and in somewhat lower yields using phosphorus(V) chemistry starting from substituted salicyl alcohols 6a-h. The phosphotriesters 3 were obtained without stereochemical preference with respect to the configuration at the phosphorus center as 1:1 diastereomeric mixtures. However, a few of the triesters 3 could be separated into the diastereomers by means of semipreparative HPLC. In a 1-octanol/phosphate buffer mixture, all compounds 3 exhibited 9-100-fold higher lipophilicity as judged from their Pa values as compared to d4T (1). Furthermore, in hydrolysis studies 3 decomposed under mild aqueous basic conditions releasing solely d4TMP (2) and the diols 6 following the designed tandem reaction sequence. A correlation of the electronic properties introduced by the substituents and the half-lives of triesters 3 was observed. Thus, by varying the substituent, the half-lives of 3 could be adjusted over a wide range of compounds still delivering d4TMP (2) selectively. Phosphotriesters 3 exhibited considerable activity against HIV-1 and HIV-2 in wild-type human T-lymphocyte (CEM/O) cells as well as mutant thymidine kinase-deficient (CEM/TK-) cells. Surprisingly, we observed a 3-80-fold difference in antiviral activity between the two diastereomers. Our data clearly prove that the cycloSal-d4TMPs deliver exclusively the nucleotide d4TMP not only under simulated hydrolysis conditions but also under cellular conditions and thus fulfill the thymidine kinase-bypass premise. Therefore, the cycloSal-nucleotide concept is the first reported pro-nucleotide system that delivers the dideoxynucleotide by a pH-driven, chemically activated, tandem reaction without the requirement of an enzymatic contribution.
报道了抗艾滋病毒双脱氧核苷2'，3'-二脱氧-2'，3'-二脱氢胸苷（d4T，1）的新型亲脂性环Sal-d4TMP衍生物3a-h的合成、水解及抗病毒评价。该前药核苷酸概念旨在通过选择性化学水解来递送d4TMP（2）。所有化合物3a-h均使用磷（III）化学以良好的产率合成，而从取代的水杨醇6a-h开始使用磷（V）化学时产率稍低。得到的磷酸三酯3在磷中心的构型方面没有立体化学偏好，为1:1的非对映异构体混合物。然而，一些磷酸三酯3可以通过半制备高效液相色谱法分离为非对映异构体。在1-辛醇/磷酸盐缓冲液混合物中，根据其Pa值判断，所有化合物3的亲脂性比d4T（1）高9-100倍。此外，在水解研究中，3在温和的碱性水溶液条件下分解，按照设计的串联反应顺序仅释放出d4TMP（2）和二醇6。观察到取代基引入的电子性质与磷酸三酯3的半衰期之间的相关性。因此，通过改变取代基，可以在仍能选择性递送d4TMP（2）的多种化合物范围内调节3的半衰期。磷酸三酯3在野生型人T淋巴细胞（CEM/O）细胞以及突变型胸苷激酶缺陷（CEM/TK-）细胞中对HIV-1和HIV-2表现出相当大的活性。令人惊讶的是，我们观察到两种非对映异构体之间的抗病毒活性存在3-80倍的差异。我们的数据清楚地证明，环Sal-d4TMP不仅在模拟水解条件下，而且在细胞条件下都仅递送核苷酸d4TMP，从而满足了胸苷激酶旁路的前提。因此，环Sal-核苷酸概念是首次报道通过pH驱动、化学活化的串联反应递送双脱氧核苷酸而无需酶参与的前药核苷酸系统。
