9-[2-(Thiophosphonomethoxy) ethyl] adenine [S-PMEA, 8] and (R)-9-[2-( Thiophosphonomethoxy) propyl] adenine [S-PMPA, 9] are acyclic nucleoside thiophosphonates we described recently that display the same antiviral spectrum (DNA viruses) as approved and potent phosphonates PMEA and (R)-PMPA. Here, we describe the synthesis, antiviral activities in infected cell cultures and decomposition study of bis ( ...