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 micrograms/ml) against different HIV-1 strains (IIIB, RF, NDK, and an AZT-resistant strain) in different cell lines (MT-4 and C-8166 cells), while it was cytotoxic at 77.7 micrograms/ml, resulting in a selectivity index of 34. This compound was inactive against HIV-2 (ROD) and SIV (MAC251). From "time-of-addition" experiments compound 21, like AZT, appeared to inhibit HIV-1 at the reverse transcriptase step.