The synthesis, anti-HIV-l and anti-herpesvirus activities of new rigid
acyclonucleotide analogs are described. -[2-methylidene-3-(phosphonom
ethoxy)propyl]guanine 1a exhibits in vitro anti-HIV-1 activity similar
to that of the antiviral agent 9-[2-(phosphonomethoxy)ethyl]adenine (
PMEA). Compound la is 9-fold less toxic to human T-lymphoid cells MT-4
than PMEA.