| abstract |
A hepatitis C virus (HCV) NS3 protease inhibitor is provided. A compound of formula I or a pharmaceutically acceptable salt thereof. (R1 and R1 ′ are independently H or substituted C1-6 aliphatic, or R1 and R1 ′ are taken together to form a 3- to 7-membered carbocycle; R2a is —OH or —NHSO2R2; R3 is a warhead group or R3 And R1 are 4 to 7-membered heterocycle having 1 to 2 hetero atoms selected from N, O or S together with intervening atoms. |