In its many embodiments, the present invention provides a novel class of pyrazolo[1,5-a]pyrimidine compounds as inhibitors of protein and/or checkpoint kinases, methods of preparing such compounds, pharmaceutical compositions including one or more such compounds, methods of preparing pharmaceutical formulations including one or more such compounds, and methods of treatment, prevention, inhibition, or amelioration of one or more diseases associated with the protein or checkpoint kinases using such compounds or pharmaceutical compositions. The invention also relates to the inhibition of hepatitis C virus (HCV) replication. In particular, embodiments of the invention provide compounds and methods for inhibiting HCV RNA-dependent RNA polymerase enzymatic activity. The invention also provides compositions and methods for the prophylaxis and treatment of HCV infection.