Iminosugars or azasugars,which exhibit effective inhibition against carbohydrate-processing enzymes,have attracted great interest for their potential clinical applications as anti-HIV,anti-diabetic,and anti-cancer agents and immunomodulators in past decades1.The bicyclic azasugars,including the naturally occurring and the synthetic compounds,have also been paid much attention due to their increased possibility leading to discovering new biologically active therapeutic agents2.The promising activities and the potential applications in clinic trial of the azasugars inspired us to explore its innovative analogs to develop novel iminosugar-based drugs3.Recently,by using microwave-assisted one-pot tandem Staudinger/aza-Wittig/condensation reaction,we have conveniently synthesized a series of bi/tricyclic azasugars fused thiazolidin-4-one and thiazinan-4-one as potential HIV reverse transcriptase(HIV-RT)inhibitors4.As continuations,considering the flexibility of the seven-membered ring,novel seven-membered iminosugars fused thiazolidin-4-one or thiazinan-4-one were designed and synthesized.The biological evaluation indicated that such bi/tricyclic azasugar hybrids exhibited better HIV-RT inhibitory activity in the preliminary HIV-RT inhibition test.