The invention is directed to 5,6-dihydro-1H-pyridin-2-one compounds of Formula I and pharmaceutical compositions containing such compounds that are useful in treating hepatitis C virus infections: ##STR00001## wherein Z is ##STR00002## X is N or CR.sup.9; Y is --(CR.sup.4R.sup.5).sub.n--; n is 2, 3, 4, or 5; and R.sup.1 through R.sup.9 are defined herein.