Capped dipeptide α-Ketoacid inhibitors of the HCV NS3 protease

The N-terminal aminoacid of α-ketotripeptide inhibitors of the hepatitis C virus NS3 protease can be replaced with an α-hydroxy acid, leading to capped dipeptide inhibitors such as 20 with an IC50 value of 3.0 μM. The importance of the lipophilic side chain interactions at S3 of the protease and the requirement of the capping residue with R configuration have been explained by molecular modeling studies.