Differential antiherpes activity of the (E)-and (Z)-isomers of 5-(2-fluorovinyl)-2'-deoxyuridine (FVUdR).

Four novel analogues of (E)-5-(2-bromovinyl)-2'-deoxyuridine [(E)-BrVUdR]--the (E)- and (Z)-isomer of 5-(2-fluorovinyl)-UdR (FVUdR), (Z)-5-(2-carboxy-2-fluorovinyl)-UdR [(Z)-COOH-FVUdR], and (E)-5-(2-ethoxyvinyl)-UdR [(E)-EOVUdR] were compared with the reference compounds (E)-BrVUdR and 5-vinyl-UdR (VUdR) for their inhibitory effects on plaque formation of herpes simplex virus type 1 (HSV-1 strain 77) and type 2 (HSV-2 strain 82) in human embryonic lung fibroblast (HELF) cell cultures. (Z)-FVUdR and (Z)-COOH-FVUdR were completely inactive against HSV-1 and HSV-2 (ID50 greater than 500 microM). For the other analogues the following order of decreasing potency was found: (E)-BrVUdR greater than VUdR greater than (E)-FVUdR much greater than (E)-EOVUdR (against HSV-1) and VUdR much greater than (E)-BrVUdR greater than (E)-FVUdR much greater than (E)-EOVUdR (against HSV-2).