Infections caused by hepatitis C virus (HCV) are a significant world health problem for which novel therapies are in urgent demand. The polymerase of HCV is responsible for the replication of viral RNA. We recently disclosed dihydroxypyrimidine carboxylates 2 as novel, reversible inhibitors of the HCV NS5B polymerase. This series was further developed into 5, 6-dihydroxy-2-(2-thienyl) pyrimidine-4-carboxylic acids such as 34 (EC50 9.3 μM), which ...