Targeting dual tolerant regions of binding pocket: Discovery of novel morpholine-substituted diarylpyrimidines as potent HIV-1 NNRTIs with significantly improved water solubility.

To address the intractable issues of drug resistance and poor solubility, a novel series of morpholine-substituted diarylpyrimidines targeting the tolerant region I and tolerant region II of NNIBP were rationally designed by utilizing the available crystallography studies. The biological evaluation results showed that four most promising compounds (14e1, 14g1, 14g2 and 14j2) displayed excellent potency against WT HIV-1 strain with EC50 values ranging from 58 to 87 nM, being far more potent than NVP and comparable to ETV. Besides, some derivatives exhibited moderate activity in inhibiting the mutant HIV-1 strains. More encouragingly, 14d2 (RF = 0.4) possessed higher antiresistance profile than ETV (RF = 6.3) and K-5a2 (RF = 3.0) toward the double mutant strain F227L + V106A. The HIV-1 RT inhibition assay confirmed their binding target. The molecular docking studies were conducted and discussed in detail to rationalize the preliminary SARs. Further test indicated that morpholine could indeed promote the improvement of water solubility. Additionally, the in silico prediction of physicochemical properties and CYP enzymatic inhibitory ability were investigated to evaluate their drug-like features.