Disclosed herein are hepatitis C viral protease inhibitors of formula (I):
##STR1##
wherein a is 0 or 1; b is 0 or 1; Y is H or C.sub.1-6 alkyl;
B is H, an acyl derivative or a sulfonyl derivative;
R.sub.6, when present, is C.sub.1-6 alkyl substituted with carboxyl;
R.sub.5, when present, is C.sub.1-6 alkyl optionally substituted with
carboxyl;
R.sub.4 is C.sub.1-10 alkyl, C.sub.3-7 cycloalkyl or C.sub.4-10
(alkylcycloalkyl);
R.sub.3 is C.sub.1-10 alkyl optionally substituted with carboxyl, C.sub.3-7
cycloalkyl or C.sub.4-10 (alkylcycloalkyl);
R.sub.2 is CH.sub.2 --R.sub.20, NH--R.sub.20, O--R.sub.20 or S--R.sub.20 ;
wherein R.sub.20 is a saturated or unsaturated C.sub.3-7 cycloalkyl or
C.sub.4-10 (alkyl cycloalkyl) being optionally mono-, di- or
tri-substituted with
R.sub.21, or R.sub.20 is a C.sub.6 or C.sub.10 aryl, C.sub.7-16 aralkyl,
Het or (lower alkyl)-Het, all optionally mono-, di- or tri-substituted
with R.sub.21, wherein R.sub.21 is as defined herein;
R.sub.1 is C.sub.1-6 alkyl, C.sub.2-6 alkenyl or C.sub.2-6 alkynyl, all
optionally substituted with halogen; and
W is hydroxy or a N-substituted amino: or W taken together with the
carbonyl group to which it is bonded represents an ester group, or a
pharmaceutically acceptable salt thereof.
