Anti-HIV Agents. Part 55: 3′R,4′R-Di-(O)-(−)-camphanoyl-2′,2′-dimethyldihydropyrano[2,3-f]chromone (DCP), a Novel Anti-HIV agent

3′R,4′R-Di-O-(−)-camphanoyl-2′,2′-dimethyldihydropyrano[2,3-f]chromone (DCP) (2) was designed and synthesized on the basis of a structure–activity relationship study of 3′R,4′R-di-O-(−)-camphanoyl-(+)-cis-khellactone DCK (1) and its analogues. DCP (2), a pyranochromone, and DCK (1), a pyranocoumarin, have different skeletons. Compound 2 showed potent in vitro inhibition of HIV-1 replication in H9 lymphocyte cells with an EC50 of 6.78×10−4 μM and TI of 14,500. These values are comparable with those for DCK (1) and better than those of AZT in the same assay.