Title : Synthesis of Gemcitabine Phosphotriester Hybrids and Their Initial in Vitro Evoluation
A number of important biological properties is assigned to the analogs of nitrogen bases, pyrimidine and purine nucleosides, and nucleotides. These are mainly antitumor and antiviral activities, but also antibacterial, antiparasitic, antifungal, and antimalarial. Currently, there are over forty effective analogues which have been approved by the US Food and Drug Administration (FDA). Gemcitabine (2´,2´-difluoro-2´-deoxycytidine (dFdC)) is one of interesting examples of this group of cytostatic agents. dFdC is the only cytidine analogue approved by the FDA which effectively affects solid tumors. Among others, it is used to treat metastatic pancreatic, ovarian or non-small cell lung cancer . We present here a general synthesis’ method of gemcitabine phosphotriester hybrids with other nucleoside analogues and non-nucleoside compounds of both natural and synthetic origin. To the bioconjugation there were used among others 3’-azido-3’-deoxythymidine (AZT), metronidazole (1-[2-hydroxyethyl]-2-methyl-5-nitroimidazole, MTZ) or metformin. The first approach was based on the triester method with 1-(mesitylene-2-sulfonyl)-3-nitro-1H-1,2,4- triazole (MNST) via coupling reagent. In comparison, in the second approach there was used only 4-chlorophenyl phosphoroditriazolide as a phosphorylating agent prepared by reaction of 4-chlorophenyl phosphorodichloridate with 1,2,4-triazole in the presence of triethylamine in acetonitrile without MNST . We also present the initial cytotoxic activity of the target 5´-phosphoramidates derivatives. This parameter was determined as a result of the sulforhodamine B test (SRB). The compounds were tested against five human cancer cell lines: cervical (HeLa), nasopharyngeal (KB), liver (HepG2), lungs (A-549), glioblastoma (U87), and also normal human dermal fibroblast cell line (HDF).