New hydroxyethylamine HIV protease inhibitors that suppress viral replication

Article abstract of DOI:10.1021/jm00099a008

The synthesis of analogues of AcSerLeuAsn[Phe-HEA-Pro]IleValOMe (1, JG- 365; where HEA stands for the hydroxyethylamine unit 2), a tight-binding inhibitor of HIVP, are reported. Systematic modification of the P₃ and P₃' regions of the inhibitors has led to smaller HIVP inhibitors that inhibit viral replication in HIV-infected and SIV-infected cell cultures. Six aliphatic and/or aromatic derivatives were prepared by replacing residues in the P₃ regions of BocLeuAsn[Phe-HEA-Pro]IleValOMe. Aromatic side chains at P₃ gave better inhibitors than aliphatic side chains. The better inhibitors in this series contained a β-naphthylalanine or a biphenyl unit at P₃. A second series of HIVP inhibitors were obtained by converting the P₃ group into acyl groups. CbzAsn[Phe-HEA-Pro]IlePheOMe and Qua-Asn-[Phe-HEA-Pro]-Ile- Phe-OMe (where Qua = quinolin-2-ylcarbonyl) are potent HIVP inhibitors with K(i) values equal to 1.0 and 0.1 nM, respectively. The inhibition constants were determined by using the continuous fluorometric assay developed by Toth and Marshall. The activities of the protease inhibitors for inhibition of SIV replication were determined in vitro using CEMx174 cells. Inhibition of HIV infection was determined essentially as reported by Pauwels and co-workers. The anti-HIV assay was carried out in culture using CEM cells (a CD4+ lymphocyte line) infected with virus strain HTLV-III(b) with a multiplicity of infection of 0.1. Several analogues inhibited the cytopathic effect at concentrations of 0.1-0.8 μg/mL. These results establish that good inhibitors of HIV protease that inhibit viral replication in infected lymphocytes in in vitro cell assays can be obtained from JG-365 when the AcSerLeu unit is replaced by aromatic acyl derivatives.