Sulfonyl-Containing Nucleoside Phosphotriesters and Phosphoramidates as Novel Anticancer Prodrugs of 5-Fluoro-2´-Deoxyuridine-5´- Monophosphate (FdUMP) Yuan-Wan Sun, Kun-Ming Chen, and Chul-Hoon Kwon†,* †Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John’s University, Jamaica, New York 11439 * To whom correspondence should be addressed. Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John’s University, 8000 Utopia parkway, Jamaica, NY 11439. Tel: (718)-990-5214, fax: (718)-990-6551, e-mail:
[email protected]. Abstract A series of sulfonyl-containing 5-fluoro-2´-deoxyuridine (FdU) phosphotriester and phosphoramidate analogues were designed and synthesized as anticancer prodrugs of FdUMP. Stability studies have demonstrated that these compounds underwent pH dependent β-elimination to liberate the corresponding nucleotide species with half-lives in the range of 0.33 to 12.23 h under model physiological conditions in 0.1M phosphate buffer at pH 7.4 and 37 °C. Acceleration of the elimination was observed in the presence of human plasma. Compounds with FdUMP moiety (4-9) were considerably more potent than those without (1-3) as well as 5-fluorouracil (5-FU) against Chinese hamster lung fibroblasts (V-79 cells) in vitro. Addition of thymidine (10 µM) reversed the growth inhibition activities of only 5-FU and the compounds with FdUMP moiety, but had no effect on those without. These results suggested a mechanism of action of the prodrugs involving the intracellular release of FdUMP. Introduction 5-Fluoro-2´-deoxyuridine-5´-monophosphate (FdUMP) is the major metabolite responsible for the anticancer activity of 5-FU (Chart 1).