Disclosed herein are compounds of formula (1): ##STR1## wherein R.sup.1 is hydroxy or NHSO.sub.2 R.sup.1A wherein R.sup.1A is (C.sub.1-8)alkyl, (C.sub.3-7)cycloalkyl or {(C.sub.1-6)alkyl-(C.sub.3-7)cycloalkyl}, which are all optionally substituted from 1 to 3 times with halo, cyano, nitro, O--(C.sub.1-6)alkyl, amido, amino or phenyl, or R.sup.1A is C.sub.6 or C.sub.10 aryl which is optionally substituted from 1 to 3 times with halo, cyano, nitro, (C.sub.1-6)alkyl, O--(C.sub.1-6) alkyl, amido, amino or phenyl; R.sup.2 is (C.sub.4-6)cycloalkyl; R.sup.3 is t-butyl or (C.sub.5-6) cycloalkyl and R.sup.4 is (C.sub.4-6)cycloalkyl; or a pharmaceutically acceptable salt thereof. The compounds are useful as inhibitors of HCV NS3 protease.

São divulgados nisto os compostos da fórmula (1): ## do ## STR1 wherein R.sup.1 é hydroxy ou NHSO.sub.2 R.sup.1A wherein R.sup.1A é (C.sub.1-8)alkyl, (C.sub.3-7)cycloalkyl ou {(C.sub.1-6)alkyl-(C.sub.3-7)cycloalkyl}, que são tudo substituiu opcionalmente 1 a 3 vezes com o halo, cyano, nitro, O -- (C.sub.1-6)alkyl, amido, amino ou phenyl, ou R.sup.1A é o arilo C.sub.6 ou C.sub.10 que é substituído opcionalmente 1 a 3 vezes com o halo, cyano, nitro, (C.sub.1-6)alkyl, O -- (C.sub.1-6) alkyl, amido, amino ou phenyl; R.sup.2 é (C.sub.4-6)cycloalkyl; R.sup.3 é t-t-butyl ou o cycloalkyl (C.sub.5-6) e R.sup.4 são (C.sub.4-6)cycloalkyl; ou um sal pharmaceutically aceitável disso. Os compostos são úteis como inibidores do protease de HCV NS3.