Synthesis of tetrazole ribonucleosides and their evaluation as antiviral agents

Synthesis of 1-beta-D-ribofuranosyltetrazole and two 5-substituted derivatives, i.e., the 5-carboxamide and 5-acetamide, is described. The stereochemical structure of the parent tetrazole ribonucleoside has been established by means of nuclear Overhauser effect and x-ray crystallography. By analogy to the parent compound, the two 5-substituted tetrazole nucleosides are also assigned the beta configuration on the basis of the NMR coupling constant of the anomeric proton and the site of N-ribosylation is determined by 13C NMR studies. Results are also presented on antiviral testing of these synthetic tetrazole nucleosides against influenza A2/Asian/J-305 virus infection in mice.