In turn, compounds 23 and 24 (ATSAO-T) were studied as reverse transcriptase inhibitors against human immunodeficiency viruses (HIV-1, IIIB and HIV-2, ROD) in human T-lymphocytes (MT-4). Notably, the oxygencontaining analogs of sultams, e.g. cyclic sulfonates (sultones), exhibited superior efficacy against DNA viruses or retroviruses under specific conditions. Among the tested compounds, sultone 25a (TSAO-T) and its N-methylsubstituted derivative 25b (TSAO-m3) demonstrated significant activity, surpassing aza-analogs 24 with an EC50 0.057 µM against HIV-1 (HIV-1, III B) and HIV-2 (HIV-2, ROD) in human T-lymphocytes (MT-4, T-cells). Additionally, certain 3,3,6-trisubstituted pyridosultones 26 emerged as potent inhibitors of HIV-1 (HIV-1, III B) with EC50 17-22 µM. However, their anti-HIV-1 activity was up to three orders lower than that of TSAO-m3 and TSAO-T. These pyridosultones 26, however, exhibited considerable activity against vesicular stomatitis virus and respiratory syncytial virus. In turn, the related monocyclic sultone 27 demonstrated significant activity against human cytomegalovirus and varicella virus. Among specific physicochemical features of sultons, the use of saturated γ-sultone 28 and its homologs as alkylating agent is widely reported, while this property is not characteristic for its aza-analogs (Figure ). At the same time, partially unsaturated sultones lack the alkylating ability due to the presence of a conjugated fragment. As a result, partially unsaturated conjugated sultones could be considered as analogs of partially unsaturated sultams by their chemical behavior.