Synthesis and HIV-1 integrase inhibitory activity of spiroundecane(ene) derivatives

Fifteen 2,4-dioxaspiro[5.5]undecane ketone and 2,4-dioxa-spiro[5.5]undec-8-ene (spiroundecane(ene)) derivatives were synthesized using the Diels–Alder reaction. Inhibition of human immunodeficiency virus integrase (IN) was examined. Eight spiroundecane(ene) derivatives inhibited both 3′-processing and strand transfer reactions catalyzed by IN. SAR studies showed that the undecane core with at least one furan moiety is preferred for IN inhibition. Moreover, crosslinking experiments showed that spiroundecane derivatives did not affect IN–DNA binding at concentrations that block IN catalytic activity, indicating spiroundecane derivatives inhibit preformed IN–DNA complex. The moderate toxicity of spiroundecane(ene) derivatives encourages the further design of therapeutically relevant analogues based on this novel chemotype of IN inhibitors.