In addition to their reported antitumor activity, 3 and 4 are also reported to display significant activity against a broad spectrum of RNA viruses, including rhinovirus types lA, 13, and 56; influenza A and B; parainfluenza 1 (Sendai); and vesicular stomatis vir~ s.~~~ The target compounds 9a-f as well as the previously synthesized 1, 2, 12, and 13l were therefore also tested for antiviral activity and compared to that of 3 and 4.
