This also relates to compositions comprising at least a tetracyclic Compound substituted with heterocycle, and Methods of use for treating or Preventing hcv infection in a patient.Claim 1: a compound having the formula (1) or a pharmaceutically acceptable Salt thereof, in which a is a compound of formula (2), is a compound of the formula (3)； each occurrence of r u00b9 is independently selected from h, alkyl c u2081 u208b u2086, haloalquilo c u2081 u208b u2086 and Halo； each occurrence of r u00b9a is independently selected from h, alkyl c u2081 u208b u2086,Haloalquilo c u2081 u208b u2086 Halo, a group or a Group r u00b9 and r u00b9 which are united in the same ring, together with the carbon Atoms in the ring to which are attached, can be combined to form a c u2083 u208b u2087 condensate cycloalkyl Group, or two groups that are united in the same r u00b9a C Atom Arbon, and the carbon Atom that are common to the UnitedCan be combined to form a c u2083 u208b u2087 espiroc u00edclico cycloalkyl Group； each occurrence of r u00b9b regardless c u2081 u208b u2086 is H, alkyl, haloalquilo c u2081 u208b u2086 or Halo or a group and a Group r u00b9a r u00b9b which are united in the same ring, together with the carbon Atoms to which they are a Go, can be combined to form a c u2083 u208b u2087 condensate cycloalkyl Group,R u00b9b or a group and a Group r u00b9 which are united in the same ring, can be combined to form a Group ch u2082 Bridge that has the Formula - - - - or ch u2082ch u2082； R u00b2 c u2081 u208b u2086 is H, alkyl, cycloalkyl c u2083 u208b u2087 phenyl or Halo； r u00b3 thiazolyl or tiadiazolilo is in that Group； and the Tiadiazolilo or group may be optionally substituted by one or more carbon Atoms in the Ring with r u2076,And in that Group； and the Group tiadiazolilo can be optionally with a c u2083 u208b u2087 condensate cycloalkyl Group； each occurrence of r u2074 is independently selected from - C (o) - C (r u2077) u2082nhc (OR) or - r u2078； r u2075 repres
