The preparation of novel 5-amino or 7-hydroxy substituted pyrazolo[4,3-b]pyridine and pyrazolo[3,4-c]pyridine acyclic C-nucleosides is described. Their synthesis was carried out by condensation of suitably substituted lithiated picolines with 2-benzyloxyethoxymethylchloride followed by pyrazole ring annulation. The compounds were evaluated for their antiviral activity against a wide panel of viruses