Design, synthesis and preliminary evaluation of peptidomimetic inhibitors of HIV aspartic protease with an epoxyalcohol core

Two peptidomimetic inhibitors based on a novel epoxyalcohol core were designed to target the epoxide ring at the catalytic aspartates of HIV-protease for irreversible inhibition of the enzyme. The inhibitors were synthesized with a multi-step approach which includes Horner-Emmons olefination of a phenylalanine-derived phosphono ketone, stereoselective reduction of the resulting trans-enones to allylic alcohols and syn-epoxidation of the latters. The epoxyalcohols thus obtained were assayed for their ability to inhibit HIV-PR and were shown to inhibit the protease with IC50 values of 39 and 150 μM, respectively. This confirms that the designed epoxides are recognised with fairly good affinity by the enzyme’s active site, a pre-requisite for selective irreversible inhibition.