Synthesis and SAR of pyridothiazole substituted pyrimidine derived HCV replication inhibitors

Introduction of a nitrogen atom into the benzene ring of a previously identified HCV replication (replicase) benzothiazole inhibitor 1, resulted in the discovery of the more potent pyridothiazole analogues 3. The potency and PK properties of the compounds were attenuated by the introductions of various functionalities at the R1, R2 or R3 positions of the molecule (compound 3). Inhibitors 38 and 44 displayed excellent potency, selectivity (GAPDH/MTS CC50), PK parameters in all species studied, and cross genotype activity.