the invention provides novel nucleosides and related processes , pharmaceutical compositions , and methods . the novel nucleosides are useful in a wide variety of antiviral , antineoplastic , and antibacterial applications . preferred embodiments of the instant invention include novel 2 halogen - substituted , 3 halogen - substituted , and 2 ′, 3 ′ dihalogen - substituted analogues of 3 - deazaadenosine , and novel 3 halogen - substituted analogues of 3 - deazaguanosine . compounds of the instant invention , including 4 - amino - 6 - fluoro - 1 - imidazopyridine and 6 - amino - 7 - bromo - 1 , 5 - dihydro - 1 - β - d - ribofuranosylimidazopyridin - 4 - one , have exhibited potent antiviral and anticancer activity in vitro . the compounds are also useful in the concomitant treatment of bacterial infections associated with viral infections such as aids .