Discovery of Novel Diarylpyrimidine Derivatives as Potent HIV‑1 NNRTIs Targeting the “NNRTI Adjacent” Binding Site

A novel series of diarylpyrimidine derivatives, which could simultaneously occupy the classical NNRTIs binding pocket (NNIBP) and the newly reported “NNRTI Adjacent” binding site, were designed, synthesized, and evaluated for their antiviral activities in MT-4 cell cultures. The results demonstrated that six compounds (<b>20</b>, <b>27</b> and <b>31</b>–<b>34</b>) showed excellent activities against wild-type (WT) HIV-1 strain (EC₅₀ = 2.4–3.8 nM), which were more potent than that of ETV (EC₅₀ = 4.0 nM). Furthermore, <b>20</b>, <b>27</b>, <b>33</b>, and <b>34</b> showed more potent or equipotent activity against single mutant HIV-1 strains compared to that of ETV. Especially, <b>20</b> showed marked antiviral activity, which was 1.5-fold greater against WT and 1.5- to 3-fold greater against L100I, K103N, Y181C, Y188L, and E138K when compared with ETV. In addition, all compounds showed lower toxicity (CC₅₀ = 5.1–149.2 μM) than ETV (CC₅₀ = 2.2 μM). The HIV-1 RT inhibitory assay was further conducted to confirm their binding target. Preliminary structure–activity relationships (SARs), molecular modeling, and calculated physicochemical properties of selected compounds were also discussed comprehensively

Further Exploring Solvent-Exposed Tolerant Regions of Allosteric Binding Pocket for Novel HIV‑1 NNRTIs Discovery

Based on the detailed analysis of the binding mode of diarylpyrimidines (DAPYs) with HIV-1 RT, we designed several subseries of novel NNRTIs, with the aim to probe biologically relevant chemical space of solvent-exposed tolerant regions in NNRTIs binding pocket (NNIBP). The most potent compound <b>21a</b> exhibited significant activity against the whole viral panel, being about 1.5–2.6-fold (WT, EC₅₀ = 2.44 nM; L100I, EC₅₀ = 4.24 nM; Y181C, EC₅₀ = 4.80 nM; F227L + V106A, EC₅₀ = 17.8 nM) and 4–5-fold (K103N, EC₅₀ = 1.03 nM; Y188L, EC₅₀ = 7.16 nM; E138K, EC₅₀ = 3.95 nM) more potent than the reference drug ETV. Furthermore, molecular simulation was conducted to understand the binding mode of interactions of these novel NNRTIs and to provide insights for the next optimization studies