Compounds of formula I: wherein R1 is hydroxy or NHSO2R1A wherein R1A is (C1-8)alkyl, (C3-7)cycloalkyl or {(C1-6)alkyl-(C3-7)cycloalkyl}, which are all optionally substituted from 1 to 3 times with halo, cyano, nitro, O(C1-6)alkyl, amido, amino or phenyl, or R1A is C6 or C10 aryl which is optionally substituted from 1 to 3 times with halo, cyano, nitro, (C1-6)alkyl, O(C1-6)alkyl, amido, amino or phenyl; R2 is (C5-6)cycloalkyl and R3 is cyclopentyl; or a pharmaceutically acceptable salt thereof, useful as inhibitors of the HCV NS3 protease.