Synthesis and biological activity of 5 fluoro 4' thiouridine and some related nucleosides

Article abstract of DOI:10.1021/jm00242a004

The synthesis of a series of 4' thio 5 halogenopyrimidine nucleosides, including the 5 fluoro, chloro, bromo and iodo derivatives, has been carried out by condensation of the 2,4 bis O trimethylsilyl derivatives of the corresponding pyrimidine bases with the protected 4 thio D ribofuranosyl chloride. Among these, the α and β anomers of 4' thio 5 fluorouridine inhibited the growth of leukemia L1210 cells at concentrations of 4 x 10^-7 and 2 x 10^-7 M, respectively, and that of S. faecium at 4 x 10^-9 and 6 x 10^-10 M, respectively. These compounds retained marked activity against strains of S. faecium resistant to 10^-3 M 5 fluorouracil or 5 fluorouridine. As determined in S. faecium cultures, 4' thio 5 fluorouridine decreased the total protein content of the cells more markedly than it did their RNA or DNA content. X Ray crystallography showed that substitution of sulfur for the oxygen in the carbohydrate ring markedly changes the conformation of that moiety.