Inhibition of human immunodeficiency virus type (HIV-1) replication by some diversely functionalized spirocyclopropyl derivatives

Inhibition of HIV-1 replication by differently substituted spirocyclopropyl compounds has been evaluated. Compound 21 showed;a moderate activity (EC50 ranging from 2.3 to 5.8 mu g/ml) against different HIV-1 strains (IIIB, RF , NDK, and an AZT resistant strain) in different cell lines (MT-4 and C-816 6 cells), while it was cytotoxic at 77.7 mu g/ml, resulting in a selectivit y index of 34. This compound was inactive against HIV-2 (ROD) and SIV(MAC25 1). From "time-of-addition" experiments compound 21, like AZT, appeared to inhibit HIV-1 at the reverse transcriptase step.