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In order to enhance the anti-HIV-1 potency and selectivity of the previously reported compound 3 (EC 50  = 27 nM, SI = 1361), a series of novel biphenyl-diarylpyrimidine derivatives were developed by employing structure-based drug design strategy. Among these derivatives, compound M44 demonstrated the most potent inhibitory activity against wild-type (WT) HIV-1 as well as five drug-resistant mutants (EC 50  = 5-148 nM), which were 5-173 times more potent than that of 3 (EC 50  = 27-9810 nM). Furthermore, this analogue exhibited approximately 11-fold lower cytotoxicity (CC 50  = 54 μM) than that of etravirine and rilpivirine. Concurrently, it possessed an improved selectivity index (SI) of 10995. Additionally, compound M44 was characterized by favorable metabolic stability in human plasma and human liver microsomes. No acute toxicity or organ damage was observed at a dose of 2 g/kg. Overall, M44 represents a highly promising lead compound that warrants further optimization efforts to identify potential anti-HIV-1 drug candidates., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier Masson SAS. All rights reserved.)

To promote the development of the new generation of HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs), a series of novel 2,4,5-trisubstituted pyrimidine derivatives targeting the "tolerant region I″ and "tolerant region II" of NNRTI binding pocket (NNIBP) were designed through multi-site binding strategy. Among them, 13a was demonstrated with an improved potency against wild-type (WT) and a panel of mutant HIV-1 strains with EC 50 values ranging from 0.0062 to 0.25 μM, being superior to that of efavirenz (EFV, EC 50  = 0.0080-0.37 μM). In addition, 13a was proved to have low cytotoxicity (CC 50  = 160.7 μM) and high SI values (SI = 25254). Further HIV-1 RT inhibition assay demonstrated that 13a is a classical NNRTI with an IC 50 value of 0.41 μM. Molecular docking and molecular dynamics simulations results illustrated its binding mode with HIV-1 RT. Overall, these enchanting results illuminated the potential of 13a as a promising lead for the development of the new generation HIV-1 NNRTIs drugs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025. Published by Elsevier Masson SAS.)

As an important part of anti-AIDS therapy, HIV-1 non-nucleoside reverse transcriptase inhibitors are plagued by resistance and toxicity issues. Taking our reported XJ-18b1 as lead compound, we designed a series of novel diarypyrimidine derivatives by employing a scaffold hopping strategy to discover potent NNRTIs with improved anti-resistance properties and drug-like profiles. The most active compound 3k exhibited prominent inhibitory activity against wild-type HIV-1 (EC 50  = 0.0019 μM) and common mutant strains including K103 N (EC 50  = 0.0019 μM), L100I (EC 50  = 0.0087 μM), E138K (EC 50  = 0.011 μM), along with low cytotoxicity and high selectivity index (CC 50  = 21.95 μM, SI = 11478). Additionally, compound 3k demonstrated antiviral activity against HIV-2 with EC 50 value of 6.14 μM. The enzyme-linked immunosorbent assay validated that 3k could significantly inhibit the activity of HIV-1 reverse transcriptase (IC 50  = 0.025 μM). Furthermore, molecular dynamics simulation studies were performed to illustrate the potential binding mode and binding free energy of the RT-3k complex, and in silico prediction revealed that 3k possessed favorable drug-like profiles. Collectively, 3k proved to be a promising lead compound for further optimization to obtain anti-HIV drug candidates., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) play a crucial role in combination antiretroviral therapy (cART). To further enhance their antiviral activity and anti-resistance properties, we developed a series of novel NNRTIs, by specifically targeting tolerant region I of the NNRTI binding pocket. Among them, compound 9t-2 displayed excellent anti-HIV-1 potency against wild-type and prevalent mutant strains with EC 50 values between 0.0019 and 0.012 μM. This outperformed the positive drugs ETR, NVP and RPV. Aslo, ELISA results confirmed that these compounds can effectively inhibit the activity of HIV-1 RT. Molecular dynamics (MD) simulation studies indicated that the thiomorpholine-1,1-dioxide moiety of 9t-2 is capable of establishing additional interactions with residues P225, F227 and P236 in the tolerant region I, which contributed to its enhanced activity. Compound 9t-2 possessed negligible inhibitory effect on the five main CYP isoenzymes (IC 50  > 10 μM), indicating a low potential for inducing CYP-mediated drug-drug interactions. In conclusion, compound 9t-2, with its enhanced anti-resistance properties, stands out as a promising lead compound for further optimization towards discovering the new generation of anti-HIV agents., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024. Published by Elsevier Masson SAS.)

In addressing the urgent need for novel HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) to combat drug resistance, we employed CuAAC click chemistry to construct a diverse 312-member diarylpyrimidine (DAPY) derivative library. This rapid synthesis approach facilitated the identification of A6N36, demonstrating exceptional HIV-1 RT inhibitory activity. Moreover, it was demonstrated with EC 50 values of 1.8-8.7 nM for mutant strains L100I, K103 N, Y181C, and E138K, being equipotent or superior to that of ETR. However, A6N36's efficacy was compromised against specific resistant strains (Y188L, F227L + V106A and RES056), highlighting a need for further optimization. Through scaffold hopping, we optimized this lead to develop 10c, which exhibited broad-spectrum activity with EC 50 values ranging from 3.2 to 57.5 nM and superior water solubility. Molecular docking underscored the key interactions of 10c within the NNIBP. Our findings present 10c as a promising NNRTI lead, illustrating the power of click chemistry and rational design in combatting HIV-1 resistance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Starting from our previously reported nonnucleoside reverse transcriptase inhibitor (NNRTI, 3), continuous efforts were made to enhance its potency and safety through a structure-based drug design strategy. This led to the discovery of a series of novel piperidine-biphenyl-diarylpyrimidines (DAPYs). Compound 10p, the most active compound in this series, exhibited an EC 50 value of 6 nM against wide-type HIV-1 strain, which was approximately 560-fold more potent than the initial compound 3 (EC 50  = 3.36 μM). Furthermore, significant improvements were observed in cytotoxicity and selectivity (CC 50  > 202.17 μM, SI > 33144) compared to compound 3 (CC 50  = 14.84 μM, SI = 4). Additionally, compound 10p demonstrated increased inhibitory activity against clinically mutant virus strains (EC 50  = 7-63 nM). Further toxicity evaluation revealed that compound 10p exhibited minimal CYP enzyme and hERG inhibition. Importantly, single-dose acute toxicity testing did not result in any fatalities or noticeable pathological damage in mice. Therefore, compound 10p can be regarded as a lead candidate for guiding further development of biphenyl-diarylpyrimidine NNRTIs with favorable druggability for HIV therapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

To develop more potent HIV-1 inhibitors against a variety of NNRTIs-resistant strains, a series of 5-cyano substituted diarylpyridines was designed based on the cocrystal structural analysis. Among them, I-5b showed the greatest potency (EC 50  = 5.62-171 nM) against the wild-type (WT) and mutant HIV-1 strains. Especially for K103 N, I-5b exhibited outstanding activity with EC 50 values of 9.37 nM, being much superior to that of NVP (EC 50  = 5128 nM) and EFV (EC 50  = 114 nM) and comparable to that of ETR (EC 50  = 3.45 nM). In addition, the target of all compounds was turned out to be HIV-1 RT with moderate RT enzyme inhibitory activity (IC 50  = 0.094-12.0 μM). Moreover, the binding mode of representative compounds with RT was elaborated via molecular docking., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Taking our previously reported HIV-1 NNRTIs BH-11c and XJ-10c as lead compounds, series of novel diarypyrimidine derivatives bearing six-membered non-aromatic heterocycles were designed to improve anti-resistance and drug-like profiles. According to the three rounds of in vitro antiviral activity screening, compound 12g was the most active inhibitor against wild-type and five prevalent NNRTI-resistant HIV-1 strains with EC 50 values ranging from 0.024 to 0.0010 μM. This is obviously better than the lead compound BH-11c and the approved drug ETR. Detailed structure-activity relationship was investigated to provide valuable guidance for further optimization. The MD simulation study indicated that 12g could form additional interactions with residues around the binding site in HIV-1 RT, which provided reasonable explanations for its improved anti-resistance profile compared to ETR. Furthermore, 12g showed significant improvement in water solubility and other drug-like properties compared to ETR. The CYP enzymatic inhibitory assay indicated that 12g was unlikely to induce CYP-mediated drug-drug interactions. 12g pharmacokinetics parameters were investigated and it displayed a long half-life of 6.59 h in vivo. The properties of compound 12g make it a promising lead compound for the development of new generation of antiretroviral drugs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Masson SAS.)

Following on our initial discovery of S-CN-DABOs as non-nucleoside reverse transcriptase inhibitors (NNRTIs), a series of novel S-N 3 -DABO derivatives F1-F31 were developed by substituting the cyano group of S-CN-DABOs with azide group. Some of these compounds were conferred significantly increased potency against wild-type HIV-1 and clinically observed mutant strains. Remarkably, the best compound F10 exerted a 7-fold improvement in potency (EC 50  = 0.053 μM) and 12.5-fold higher selectivity (SI = 6818) in MT-4 cells infected with wild-type HIV-1, compared to that of the parent compound B1 (EC 50  = 370 nM, SI = 547). The anti-HIV-1 activity of F10 against the tested mutant strains was prominently enhanced. For wild-type reverse transcriptase, it was approximately 19-fold more potent (IC 50  = 0.080 μM) than B1 (IC 50  = 1.51 μM). It was not found that this analog had significant inhibition of hERG, CYP, and acute toxicity after a single dose of F10 (1.0 g/kg)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Adding to past success in developing non-nucleoside reverse transcriptase inhibitors (NNRTIs), we report herein our efforts to optimize an FDA-approved NNRTI, doravirine, into a series of novel biphenyl-substituted pyridone derivatives. A strategy focused on harnessing the X-ray crystal structure of doravirine, coupled with computer simulations, to guide the design of conformationally constrained analogs led to the discovery of ZLM-66, which provided comparable inhibitory potency to doravirine against wild-type HIV-1 (EC 50  = 13 nM) and various single/double mutant strains. ZLM-66 possessed acceptable cytotoxicity and selectivity index. In vivo profiling indicated that ZLM-66 exhibited excellent pharmacokinetics with significantly improved oral bioavailability (F = 140.24%) and a more favorable half-life (T 1/2  = 8.45 h), compared to that of doravirine (F = 57%, T 1/2  = 4.4 h). In addition, ZLM-66 did not cause significant inhibition of CYP and hERG (>200 μM), as well as acute toxicity and tissue damage at a dose of 1.2 g/kg. Therefore, ZLM-66 can be used as a lead compound to further guide the development of orally active biphenyl-containing doravirine analogs for HIV therapy., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

To thoroughly investigate the uncharted chemical space around the entrance channel of HIV-1 reverse transcriptase (RT) and to improve the physicochemical properties, we introduced different spiro ring structures with high Fsp 3 values as linkers at indole-2-carboxamide, attaching to various terminal substituents to enhance the interactions with the entrance channel. All the newly designed and synthesized indolylarylsulfone (IAS) derivatives exhibited moderate to excellent potency against wild-type HIV-1 with EC 50 values ranging from 0.0053 to 0.19 μM. Among them, compounds SO-7g (EC 50  = 0.0053 μM) and SO-7h (EC 50  = 0.009 μM, SI > 21552) were identified as the most two potent compounds, which displayed 30- and 16-fold improvement than nevirapine and zidovudine and comparable potency to efavirenz and etravirine. Moreover, SO-7g maintained the promising activity against a variety of mutant strains, especially for L100I (EC 50  = 0.047 μM), K103 N (EC 50  = 0.056 μM), and E138K (EC 50  = 0.040 μM). Notably, the introduction of spiro rings could effectively reduce the cytotoxicity (CC 50 ) and greatly improve the selectivity index compared to lead compound, exemplified by SO-7h (CC 50  > 214.4 μM, SI > 21552) and SO-7a (CC 50  > 233.2 μM, SI > 20933). Additionally, the preliminary SARs based on antiviral activity and molecular simulation perspective were analyzed with a detailed description, which could point out the direction for further structural optimization., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Further clinical development of PF74, a lead compound targeting HIV-1 capsid, is impeded by low antiviral activity and inferior metabolic stability. By modifying the benzene (region I) and indole of PF74, we identified two potent compounds (7m and 7u) with significantly improved metabolic stability. Compared to PF74, 7u displayed greater metabolic stability in human liver microsomes (HLMs) with half-life (t 1/2 ) 109-fold that of PF74. Moreover, mechanism of action (MOA) studies demonstrated that 7m and 7u effectively mirrored the MOA of compounds that interact within the PF74 interprotomer pocket, showing direct and robust interactions with recombinant CA, and 7u displaying antiviral effects in both the early and late stages of HIV-1 replication. Furthermore, MD simulation corroborated that 7u was bound to the PF74 binding site, and the results of the online molinspiration software predicted that 7m and 7u had desirable physicochemical properties. Unexpectedly, this series of compounds exhibited better antiviral activity than PF74 against HIV-2, represented by compound 7m whose anti-HIV-2 activity was almost 5 times increased potency over PF74. Therefore, we have rationally redesigned the PF74 chemotype to inhibitors with novel structures and enhanced metabolic stability in this study. We hope that these new compounds can serve as a blueprint for developing a new generation of HIV treatment regimens., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier Masson SAS.)

HIV-1 capsid (CA) plays indispensable and multiple roles in the life cycle of HIV-1, become an attractive target in antiviral therapy. Herein, we report the design, synthesis, and mechanism study of a novel series of dimerized phenylalanine derivatives as HIV-1 capsid inhibitors using 2-piperazineone or 2,5-piperazinedione as a linker. The structure-activity relationship (SAR) indicated that dimerized phenylalanines were more potent than monomers of the same chemotype. Further, the inclusion of fluorine substituted phenylalanine and methoxyl substituted aniline was found to be beneficial for antiviral activity. From the synthesized series, Q-c4 was found to be the most potent compound with an EC 50 value of 0.57 μM, comparable to PF74. Interestingly, Q-c4 demonstrated a slightly higher affinity to the CA monomer than the CA hexamer, commensurate with its more significant effect in the late-stage of the HIV-1 lifecycle. Competitive SPR experiments with peptides from CPSF6 and NUP153 revealed that Q-c4 binds to the interprotomer pocket of hexameric CA as designed. Single-round infection assays showed that Q-c4 interferes with the HIV-1 life cycle in a dual-stage manner, affecting both pre-and post-integration. Stability assays in human plasma and human liver microsomes indicated that although Q-c4 has improved stability over PF74, this kind of inhibitor still requires further optimization. And the results of the online molinspiration software predicted that Q-c4 has desirable physicochemical properties but some properties still have some violation from the Lipinski rule of five. Overall, the dimerized phenylalanines are promising novel platforms for developing future HIV-1 CA inhibitors with considerable potential for optimization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

A series of novel naphthyl-diarylpyrimidine (DAPY) derivatives were designed and synthesized to explore the entrance channel of the non-nucleoside reverse transcriptase inhibitors binding pocket (NNIBP) by incorporating different flexible side chains at the C-6 position. The biological evaluation results showed that all analogues possessed promising HIV-1 inhibitory activity at the nanomolar concentration range. Three compounds (7, 9 and 39) displayed excellent potency against WT HIV-1 strain with EC 50 values ranging from 5 to 10 nM and high selectivity indexes (SI = 3504, 30488 and 22846, respectively), which were higher than for nevirapine and comparable to the values for etravirine. The RT inhibition activity, preliminary structure-activity relationship and molecular docking study showed that the side chain at the C-6 position of the DAPYs occupied the entrance channel and significantly influenced anti-HIV activity and selectivity. Additionally, the physicochemical properties were investigated to evaluate the drug-like features, which indicated that introducing various substituents on the pyrimidine ring can improve solubility., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Despite significant advances in antiretroviral therapy, acquired immunodeficiency syndrome remains as one of the leading causes of death worldwide. New antiretroviral drugs combined with updated treatment strategies are needed to improve convenience, tolerability, safety, and antiviral efficacy of available therapies. In this work, a focused library of coumarin derivatives was exploited by cell phenotypic screening to discover novel inhibitors of HIV-1 replication. Five compounds (DW-3, DW-4, DW-11, DW-25 and DW-31) showed moderate activity against wild-type and drug-resistant strains of HIV-1 (IIIB and RES056). Four of those molecules were identified as inhibitors of the viral RT-associated RNase H. Structural modification of the most potent DW-3 and DW-4 led to the discovery of compound 8a. This molecule showed increased potency against wild-type HIV-1 strain (EC 50  = 3.94 ± 0.22 μM) and retained activity against a panel of mutant strains, showing EC 50 values ranging from 5.62 μM to 202 μM. In enzymatic assays, 8a was found to inhibit the viral RNase H with an IC 50 of 12.3 μM. Molecular docking studies revealed that 8a could adopt a binding mode similar to that previously reported for other active site HIV-1 RNase H inhibitors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

With our previously identified potent NNRTIs 25a and HBS-11c as leads, series of novel thiophene[3,2-d]pyrimidine and thiophene[2,3-d]pyrimidine derivatives were designed via molecular hybridization strategy. All the target compounds were evaluated for their anti-HIV-1 activity and cytotoxicity in MT-4 cells. Compounds 16a1 and 16b1 turned out to be the most potent inhibitors against WT and mutant HIV-1 strains (L100I, K103N, and E138K), with EC 50 values ranging from 0.007 μM to 0.043 μM. Gratifyingly, 16b1 exhibited significantly reduced cytotoxicity (CC 50  > 217.5 μM) and improved water solubility (S = 49.3 μg/mL at pH 7.0) compared to the lead 25a (S < 1 μg/mL at pH 7.0, CC 50  = 2.30 μM). Moreover, molecular docking was also conducted to rationalize the structure-activity relationships of these novel derivatives and to understand their key interactions with the binding pocket., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

To yield potent HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) with favorable drug-like properties, a series of novel diarylpyrimidine derivatives targeting the tolerant region I of the NNRTI binding pocket were designed, synthesized and biologically evaluated. The most active inhibitor 10c exhibited outstanding antiviral activity against most of the viral panel, being about 2-fold (wild-type, EC 50  = 0.0021 μM), 1.7-fold (K103N, EC 50  = 0.0019 μM), and slightly more potent (E138K, EC 50  = 0.0075 μM) than the NNRTI drug etravirine (ETR). Additionally, 10c was endowed with relatively low cytotoxicity (CC 50  = 18.52 μM). More importantly, 10c possessed improved drug-like properties compared to those of ETR with an increased Fsp 3 (Fraction of sp 3 carbon atoms) value. Furthermore, the molecular dynamics simulation and molecular docking studies were implemented to reveal the binding mode of 10c in the binding pocket. Taken together, 10c is a promising lead compound that is worth further investigation., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Inspired by our previous efforts to improve the drug-resistance profiles of HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs), a novel series of "dual-site" binding diarylpyrimidine (DAPY) derivatives targeting both the NNRTI adjacent site and NNRTIs binding pocket (NNIBP) were designed, synthesized, and evaluated for their anti-HIV potency in TZM-bl and MT-4 cells. Eight compounds exhibited moderate to excellent potencies in inhibiting wild-type (WT) HIV-1 replication with EC 50 values ranging from 2.45 nM to 5.36 nM, and 14c (EC 50  = 2.45 nM) proved to be the most promising inhibitor. Of note, 14c exhibited potent activity against the single mutant strain E138K (EC 50  = 10.6 nM), being comparable with ETR (EC 50  = 9.80 nM) and 3.5-fold more potent than that of compound 7 (EC 50  = 37.3 nM). Moreover, 14c acted as a classical NNRTI with high affinity for WT HIV-1 RT (IC 50  = 0.0589 μM). The detailed structure-activity relationships (SARs) of the representative compounds were also determined, and further supported by molecular dynamics simulation. Overall, we envision that the "dual-site"-binding NNRTIs have significant prospects and pave the way for the next round of rational design of potent anti-HIV-1 agents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

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 EC 50 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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

The single enantiomers of seven hydroxyl-substituted biphenyl-diarylpyrimidines were designed and synthesized by a bioisosterism strategy as novel HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs). The cellular and enzymatic assays indicated that the novel obtained compounds had significant activities and relatively low cytotoxicity. The supercritical fluid chromatography (SFC) enantioseparations of the racemic compounds and the enantiomeric profiling resulted that the (S) forms were generally more potent than the (R) counterparts. Among all the chiral derivatives, (S)-(-)-12a showed the best potency with the antiviral activities against wild-type (WT) and single mutant strains (L100I, K103 N, Y181C, E138K; especially Y188L), and RT enzyme in the low nanomolar concentration range. Toward double mutant virus strains (F227L + V106A, RES056), (S)-(-)-12a possessed submicromolar antiviral activities. In addition, (S)-(-)-12a showed a high cell-based selectivity index (SI WT  = 5822) and no apparent toxicity was observed in the in vivo acute toxicity assay and electrocardiogram. The molecular docking studies predicted the binding modes of the compounds with RT and explained the activity differences for the enantiomers. Although the rat pharmacokinetic assay indicated a poor oral metabolism of the hydroxyl compound, the promising antiviral activity of the chiral hydroxyl-substituted biphenyl-diarylpyrimidines provided valuable lead compounds for further anti-HIV drug design., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

HIV-1 RT has been considered as one of the most important targets for the development of anti-HIV-1 drugs for their well-solved three-dimensional structure and well-known mechanism of action. In this study, with HIV-1 RT as target, we used miniaturized parallel click chemistry synthesis via CuAAC reaction followed by in situ biological screening to discover novel potent HIV-1 NNRTIs. A 156 triazole-containing inhibitor library was assembled in microtiter plates and in millimolar scale. The enzyme inhibition screening results showed that 22 compounds exhibited improved inhibitory activity. Anti-HIV-1 activity results demonstrated that A3N19 effected the most potent activity against HIV-1 IIIB (EC 50  = 3.28 nM) and mutant strain RES056 (EC 50  = 481 nM). The molecular simulation analysis suggested that the hydrogen bonding interactions of A3N19 with the main chain of Lys101 and Lys104 was responsible for its potency. Overall, the results indicated the in situ click chemistry-based strategy was rational and might be amenable for the future discovery of more potent HIV-1 NNRTIs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

The fragment hopping approach is widely applied in drug development. A series of diarylpyrimidines (DAPYs) were obtained by hopping the thioacetamide scaffold to novel human immunodeficiency virus type 1 (HIV-1) nonnucleoside reverse transcriptase inhibitors (NNRTIs) to address the cytotoxicity issue of Etravirine and Rilpivirine. Although the new compounds (11a-l) in the first-round optimization possessed less potent anti-viral activity, they showed much lower cytotoxicity. Further optimization on the sulfur led to the sulfinylacetamide-DAPYs exhibiting improved anti-viral activity and a higher selectivity index especially toward the K103N mutant strain. The most potent compound 12a displayed EC 50 values of 0.0249 μM against WT and 0.0104 μM against the K103N mutant strain, low cytotoxicity (CC 50  > 221 μM) and a high selectivity index (SI WT  > 8873, SI K103N  > 21186). In addition, this compound showed a favorable in vitro microsomal stability across species. Computational study predicted the binding models of these potent compounds with HIV-1 reverse transcriptase thus providing further insights for new developments., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

For more in-depth exploration of the chemical space around the entrance channel of HIV-1 reverse transcriptase (RT), a series of novel indolylarylsulfones (IASs) bearing different chiral N-substituted pyrrolidine, azetidine or substituted sulfonamide groups at indole-2-carboxamide were designed and synthesized as potent HIV NNRTIs by structure-guided scaffold morphing approach. All the IASs exhibited moderate to excellent potency against wild-type HIV-1 with EC 50 values ranging from 0.0043 μM to 4.42 μM. Notably, compound 27 (EC 50  = 4.7 nM, SI = 5183) and 33 (EC 50  = 4.3 nM, SI = 7083) were identified as the most potent compounds, which were more active than nevirapine, lamivudine and efavirenz, and also reached the same order of etravirine. Furthermore, some compounds maintained excellent activity against various single HIV-1 mutants (L100I, K103 N, E138K, Y181C) as well as one double mutant (F227L/V106A) with EC 50 values in low-micromolar concentration ranges. Notably, 34 displayed outstanding potency against F227L/V106A (EC 50  = 0.094 μM), and also showed exceptional activity against E138K (EC 50  = 0.014 μM), L100I (EC 50  = 0.011 μM) and K103 N (EC 50  = 0.025 μM). Additionally, most compounds showed markedly reduced cytotoxicity (CC 50 ) compared to lead compounds, especially 36 (CC 50  > 234.91 μM, SI > 18727) and 37 (CC 50  > 252.49 μM, SI > 15152). Preliminary SARs and molecular modeling studies were also discussed in detail, which may provide valuable insights for further optimization., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Conformational restriction is a promising strategy in the development of DAPY-type non-nucleoside reverse transcriptase inhibitors (NNRTIs). Herein, eighteen thiophene-biphenyl-DAPY derivatives were designed and synthesized as potent HIV-1 NNRTIs in which halogen and methyl groups were introduced to explore the conformationally constrained effects. Molecular docking and dynamic simulation analysis indicated that substituents on different positions of the biphenyl ring induced different dihedral angles and binding conformations, further explaining their anti-viral activities. The 2'-fluoro and 3'-chloro substitutions could form electrostatic or halogen-bonding interactions with adjacent residues of the RT enzyme. The 2'-methyl group contributed to enlarge the dihedral angle of biphenyl ring and was positioned to a space-filling hydrophobic pocket. Notably, compounds 22 and 23 with two methyl groups exhibited potent biological activity against WT HIV-1-infected MT-4 cells (EC 50  = 14 and 17 nM, respectively) and RT enzyme (EC 50  = 27 and 42 nM, respectively). In particular, 23 exhibited much lower cytotoxicity (CC 50  = 264.19 μM) and higher selectivity index (SI = 18,564) than etravirine. Taken together, a rational conformational model for further design of DAPYs is proposed, providing a new guidance for the development of NNRTIs., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

A novel series of dihydroquinazolin-2-amine derivatives were synthesized and evaluated for their anti-HIV-1 activity in MT-4 cell cultures. All of the molecules were active against wild-type HIV-1 with EC 50 values ranging from 0.61 μM to 0.84 nM. The most potent inhibitor, compound 4b, had an EC 50 value of 0.84 nM against HIV-1 strain IIIB, and thus was more active than the reference drugs efavirenz and etravirine. Moreover, most of the compounds maintained high activity (low-micromolar EC 50 values) against strains bearing the reverse transcriptase (RT) E138K mutation. Compound 4b had EC 50 values of 3.5 nM and 66 nM against non-nucleoside reverse transcriptase inhibitor-resistant strains bearing the RT E138K and RES056 mutations. In enzyme activity assays, compound 4b exhibited an IC 50 value of 10 nM against HIV-1 RT. Preliminary SARs and molecular docking studies provide valuable insights for further optimization., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

We reported herein the design, synthesis and biological evaluation of a series of 5-hydroxypyrido[2,3-b]pyrazin-6(5H)-one derivatives as HIV-1 reverse transcriptase (RT) ribonuclease H (RNase H) inhibitors using a privileged structure-guided scaffold refining strategy. In view of the similarities between the pharmacophore model of RNase H and integrase (IN) inhibitors as well as their catalytic sites, we also performed IN inhibition assays. Notably, the majority of these derivatives inhibited RNase H and IN at micromolar concentrations. Among them, compound 7a exhibited similar inhibitory activity against RNase H and IN (IC 50 RNase H  = 1.77 μM, IC 50 IN  = 1.18 μM, ratio = 1.50). To the best of our knowledge, this is the first reported dual HIV-1 RNase H-IN inhibitor based on a 5-hydroxypyrido[2,3-b]pyrazin-6(5H)-one structure. Molecular modeling has been used to predict the binding mode of 7a in complex with the catalytic cores of HIV-1 RNase H and IN. Taken together these results strongly support the feasibility of developing HIV-1 dual inhibitors from analog-based optimization of divalent metal ion chelators. Recently, the identification of dual inhibitors proved to be a highly effective strategy for novel antivirals discovery. Therefore, these compounds appear to be useful leads that can be further modified to develop more valuable anti-HIV-1 molecules with suitable drug profiles., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Inspired by our previous efforts on the modifications of diarylpyrimidines as HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTI) and reported crystallography study, novel diarylnicotinamide derivatives were designed with a "triazole tail" occupying the entrance channel in the NNRTI binding pocket of the reverse transcriptase to afford additional interactions. The newly designed compounds were then synthesized and evaluated for their anti-HIV activities in MT-4 cells. All the compounds showed excellent to good activity against wild-type HIV-1 strain with EC 50 of 0.02-1.77 μM. Evaluations of selected compounds against more drug-resistant strains showed these compounds had advantage of inhibiting E138K mutant virus which is a key drug-resistant mutant to the new generation of NNRTIs. Among this series, propionitrile (3b2, EC 50(IIIB)  = 0.020 μM, EC 50(E138K)  = 0.015 μM, CC 50  = 40.15 μM), pyrrolidin-1-ylmethanone (3b8, EC 50(IIIB)  = 0.020 μM, EC 50(E138K)  = 0.014 μM, CC 50  = 58.09 μM) and morpholinomethanone (3b9, EC 50(IIIB)  = 0.020 μM, EC 50(E138K)  = 0.027 μM, CC 50  = 180.90 μM) derivatives are the three most promising compounds which are equally potent to the marketed drug Etravirine against E138K mutant strain but with much lower cytotoxicity. Furthermore, detailed SAR, inhibitory activity against RT and docking study of the representative compounds are also discussed., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

A novel series of diarylpyrimidine (DAPY) derivatives bearing the biphenyl motif with multiple substituted groups was synthesized as human immunodeficiency virus (HIV)-1 non-nucleoside reverse transcriptase inhibitors. All of the target compounds were evaluated for their in vitro activity against HIV in MT-4 cells. Most of the compounds exhibited excellent activity with low nanomolar EC 50 values against wild-type, single and double mutant HIV-1 strains. Compound 4b displayed an EC 50 value of 1 nM against HIV-1 IIIB, 1.3 nM against L100I, 0.84 nM against K103 N, 1.5 nM against Y181C, 11 nM against Y188L, 2 nM against E138K, 10 nM against K103 N + Y181C, and almost 110 nM against F227L + V106. The improvement in the selectivity and potency of the target molecules against the wild-type and mutant HIV-1 strains validated our hypothesis. The biphenyl ring in the DAPY derivatives could strengthen the π-π stacking effect between the target molecule and the non-nucleoside inhibitor-binding pocket in the reverse transcriptase by extending the conjugating systems. This research represented a significant step toward the discovery of novel therapeutic DAPYs for treating acquired immunodeficiency syndrome in patients infected with HIV-1., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

As a continuation of our efforts to discover and develop "me-better" drugs of DAPYs, novel diarylpyridine derivatives were designed, synthesized and evaluated for their anti-HIV activities in MT-4 cells. The majority of these compounds showed high activity against wild-type HIV-1 strain (IIIB) with EC 50 values in the range of 0.04-4.41 μM. Among them, compound 5b2 (EC 50  = 0.04 μM, SI = 3963) was the most potent. This compound showed anti-HIV-1 IIIB activity superior than of Nevirapine but still inferior than of Etravirine. Selected compounds were also evaluated for the activity against reverse transcriptase (RT), and most of the compounds exhibited submicromolar IC 50 values indicating they are specific RT inhibitors. Preliminary structure-activity relationships and modeling studies of these new analogues provide valuable avenues for future molecular optimization., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

A novel series of uracil-bearing DAPYs derivatives were designed and synthesized via structure-based molecular hybridization to discover compounds with improved anti-resistance profiles. Anti-HIV activity of the designed compounds was tested in MT-4 cell cultures. The most promising compound 16d showed excellent activity with EC 50 value of 5.6 nM against wide-type HIV-1 and low cytotoxicity (SI > 50000). Activity against the clinic prevalent mutant strains was also tested, suggesting that 16d was sensitive to E138K (EC 50  = 34.2 nM). Primary drug-like properties, such as water solubility and logP, were evaluated by experiment or calculation, which indicated that introducing an uracil can improve solubility. The molecular modeling accompanied with the preliminary SAR correlations paved the way for the next round of rational design of potent anti-HIV agents., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

To further explore the chemical space around the entrance channel of HIV-1 reverse transcriptase (RT), a series of novel indolylarylsulfones (IASs) bearing N-substituted piperidine at indole-2-carboxamide were identified as potent HIV NNRTIs by structure-guided scaffold morphing and fragment rearrangement. All the IASs exhibited moderate to excellent potency against wild-type HIV-1 with EC 50 values ranging from 0.62 μM to 0.006 μM 8 (EC 50  = 6 nM) and 18 (EC 50  = 9 nM) were identified as the most potent compounds, which were more active than NVP and DLV, and reached the same order of EFV and ETV. Furthermore, most compounds maintained high activity agaist various single HIV-1 mutants (L100I, K103N, E138K, Y181C) as well as one double mutant (F227L/V106A) with EC 50 values in low-micromolar to double-digit nanomolar concentration ranges. Especially, 8 displayed outstanding potency against L100I (EC 50  = 17 nM with a 2.8-fold resistance ratio) and 18 was relatively more potent to E138K mutant (EC 50  = 43 nM with a 4.7-fold resistance ratio). Preliminary SARs and molecular modeling studies were also discussed in detail, which may provide valuable insights for further optimization., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

In this study, a series of thiosemicarbazide derivatives 12-14, 1,2,4-triazol-3-thione derivatives 15-17 and compounds bearing 2-(4H-1,2,4-triazole-3-ylthio)acetamide structure 18-32 have been synthesized starting from phenolic compounds such as 2-naphthol, paracetamol and thymol. Structures and purity of the target compounds were confirmed by the use of their chromatographic and spectral data besides microanalysis. All of the synthesized new compounds 12-32 were evaluated for their anti-HIV activity. Among these compounds, three representatives 18, 19 and 25 were selected and evaluated by the National Cancer Institute (NCI) against the full panel of 60 human cancer cell lines derived from nine different cancer types. Antiproliferative effects of the selected compounds were demonstrated in human tumor cell lines K-562, A549 and PC-3. These compounds inhibited cell growth assessed by MTT assay. Compound 18, 19 and 25 exhibited anti-cancer activity with IC50 values of 5.96 μM (PC-3 cells), 7.90 μM (A549/ATCC cells) and 7.71 μM (K-562 cells), respectively. After the cell viability assay, caspase activation and Bcl-2 activity of the selected compounds were measured and the loss of mitochondrial membrane potential (MMP) was detected. Compounds 18, 19 and 25 showed a significant increase in caspase-3 activity in a dose-dependent manner. This was not observed for caspase-8 activity with compound 18 and 25, while compound 19 was significantly elevated only at the dose of 50 μM. In addition, all three compounds significantly decreased the mitochondrial membrane potential and expression of Bcl-2., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Based on the crystallographic studies of diarylpyrimidines (DAPYs), we embarked on incorporating the hydrophilic piperidyl or morpholinyl group into the known DAPY derivatives bearing the pyridine moiety as a core structure, with the double aim to exploit additional interactions with the HIV-1 NNRTI binding pocket (NNIBP), as well as to improve the compound solubility. The antiviral evaluation result show that the most potent compounds I-8b2, I-8b3, I-8b4 and I-8c3 exhibited anti-HIV-1 (IIIB) strain activity ranging from 7.4 nM to 9.4 nM (SI = 168-1283), superior to FDA-approved drugs of nevirapine (NVP), lamivudine (3TC) and delavirdine (DLV), and comparable to etravirine (ETV), zidovudine (AZT) and efavirenz (EFV). Additionally, compounds I-8c2 and I-8c3 showed moderate activity against NNRTI resistant strains baring mutations K103N and Y181C with EC50 values of 6.2 μM and 6.8 μM, respectively. Preliminary structure-activity relationships (SARs), reverse transcriptase inhibition efficacy and molecular modeling of selected compounds are also presented. These outcomes support our design hypothesis and demonstrate that the piperidyl group modified pyridine-typed DAPY derivatives are highly potent NNRTIs with improved water solubility., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

On the basis of structure-based bioisosteric replacement and molecular hybridization strategy, a series of novel dual structural-conformation inhibitors targeting the "entrance channel" of HIV-1 NNRTIs binding pocket (NNIBP) were designed and synthesized. All of the new compounds were evaluated for their anti-HIV activities in MT-4 cells using the MTT method. Five compounds exhibited moderate to excellent potencies inhibiting wild-type (wt) HIV-1 replication with EC50 values ranging from 31.36 μM to 0.11 μM. Among them, compound 15b was identified as the most potent inhibitor with EC50 values of 0.11 μM and 2.18 μM against wt and K103N/Y181C double mutant HIV-1 strain (RES056), respectively. In addition, preliminary structure-activity relationships (SARs) and molecular simulation studies were discussed, which may provide valuable insights for further optimization., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

The development of novel NNRTIs with activity against variants of HIV-1RT is crucial for overcoming treatment failure. In the present study, a series of novel 6-substituted diarylpyridine derivatives targeting the entrance channel of the NNIBP of RT were designed through a molecular hybridization strategy. Encouragingly, these new diarylpyridine derivatives were found to be active against wild-type (WT) HIV-1 with an EC50 values ranging from 0.035 μM to 1.99 μM. Nearly half of them exhibited more potent inhibitory activities in cellular assays than the control drug nevirapine (NVP). Notably, three most promising compounds If (EC50 = 35 nM), Ia (EC50 = 43 nM) and IIa (EC50 = 41 nM) showed high potency against WT and were comparable to the reference drug delavirdine (DLV) (EC50 = 33 nM). Moreover, compounds Ib, IIb and IIh displayed effective activity against the most common clinically observed single and double-mutated HIV-1 strains in micromolar concentrations. In particular, the inhibition of IIb against the K103N mutation (EC50 = 49 nM), which confers resistance to a wide variety of NNRTIs, was about 140 times more effective than NVP (EC50 = 6.78 μM), 50 times more than DLV (EC50 = 2.48 μM) and about 3 times more than EFV (EC50 = 0.12 μM), indicating that the newly designed compounds have great potential to be further developed as new anti-HIV-1 agents. Preliminary structure-activity relationships (SARs) and molecular modeling of the new diarylpyridine derivatives were discussed in detail., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Based on molecular simulation, the etravirine-VRX-480773 hybrids previously disclosed by our group were optimized to yield novel pyrimidine sulfonylacetanilides 8 with improved activity against a panel of seven clinically relevant single and double mutant strains of HIV-1. The improvement in potency in this in vitro model of HIV RNA replication partly validates the mechanism by which this class of allosteric pyrimidine derivatives inhibits the reverse transcriptase (RT), and represents a remarkable step forward in the development of anti-HIV drugs., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

The poor pharmacokinetics, side effects and particularly the rapid emergence of drug resistance compromise the efficiency of the clinically used anti-HIV drugs. Therefore, the discovery of novel and effective NNRTIs is still an extremely primary mission. Arylthioacetanilide family is one of the highly active HIV-1 NNRTIs against wide-type (WT) HIV-1 and a wide range of drug-resistant mutant strains. Especially, VRX-480773 and RDEA806 have been chosen as candidates for further clinical studies. In this article, we review the discovery and development of the arylthioacetanilides, and, especially, pay much attention to the structural modifications, SARs conclusions and molecular modeling. Moreover, several medicinal chemistry strategies to overcome drug resistance involved in the optimization process of arylthioacetanilides are highlighted, providing valuable clues for further investigations., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

A novel series of piperidin-4-yl-aminopyrimidine derivatives were designed fusing the pharmacophore templates of etravirine-VRX-480773 hybrids our group previously described and piperidine-linked aminopyrimidines. Most compounds displayed significantly improved activity against wild-type HIV-1 with EC50 values in single-digit nanomolar concentrations compared to etravirine-VRX-480773 hybrids. Selected compounds were also evaluated for activity against reverse transcriptase, and had lower IC50 values than that of nevirapine. The improved potency observed in this in vitro model of HIV RNA replication partly validates the mechanism by which this class of allosteric pyrimidine derivatives inhibits reverse transcriptase, and represents a remarkable step forward in the development of AIDS therapeutics., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Through a structure-guided core-refining approach, a series of novel imidazo[1,2-a]pyrazine derivatives were designed, synthesized and evaluated as HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs). Biological results of antiviral assay in MT-4 cell cultures showed that 12 target compounds displayed moderate activities against wild-type (wt) HIV-1 strain (IIIB) with EC50 values ranging from 0.26 μM to 19 μM. Among them, 4a and 5a were found to be the two most active analogues possessing EC50 values of 0.26 μM and 0.32 μM respectively, comparable to delavirdine (DLV, EC50 = 0.54 μM) and nevirapine (NVP, EC50 = 0.31 μM) in a cell-based assay. Additionally, 9 compounds showed RT inhibitory activity superior to that of NVP. Moreover, some predicted drug-like properties of representative compounds 4a and 5a, as well as the structure-activity relationship (SAR) analysis were discussed in detail. The binding mode of compound 4a was investigated by molecular simulation studies., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

In our arduous efforts to develop new potent HIV-1 non-nucleoside reverse transcriptase (RT) inhibitors (NNRTIs), novel piperidine-linked [1,2,4]triazolo[1,5-a]pyrimidine derivatives were designed, synthesized and evaluated for their antiviral activities in MT-4 cell cultures. Biological results showed that all of the title compounds displayed moderate to excellent activities against wild-type (wt) HIV-1 strain (IIIB) with EC50 values ranging from 8.1 nM to 2284 nM in a cell-based assay. Among them, the most promising analog 7d possessed an EC50 value of 8.1 nM against wt HIV-1, which was much more potent than the reference drugs DDI, 3 TC, NVP and DLV. Additionally, 7d demonstrated weak activity against the double mutant HIV-1 strain (K103N + Y181C), and was more efficient than NVP in a RT inhibition assay. Besides, some measured and calculated physicochemical properties of 7d, like log P and water solubility, as well as the structure-activity relationships (SARs) analysis have been discussed in detail. Furthermore, the binding mode of the active compound 7d was rationalized by molecular simulation studies., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Through a structure-based molecular hybridization approach, a novel series of diarylnicotinamide derivatives (DANAs) targeting the entrance channel of HIV-1 NNRTIs binding pocket (NNIBP) were rationally designed, synthesized and evaluated for their anti-HIV activities in MT-4 cells together with the inhibition against the reverse transcriptase (RT) in an enzymatic assay. Encouragingly, most of the new DANAs were found to be active against wild-type HIV-1 with an EC50 in the range of 0.027-4.54 μM. Among them, compound 6b11 (EC50 = 0.027 μM, SI > 12518) and 6b5 (EC50 = 0.029 μM, SI = 2471) were identified as the most potent inhibitors, which were more potent than the reference drugs nevirapine (EC50 = 0.31 μM) and delavirdine (EC50 = 0.66 μM). Some DANAs were also active at micromolar concentrations against the K103N + Y181C resistant mutant. Compound 6b11 exhibited the highest enzymatic inhibition activity (IC50 = 20 nM), which is equal to that of efavirenz (EC50 = 20 nM) and 31 times higher than that of nevirapine (EC50 = 0.62 μM). Preliminary structure-activity relationships (SARs) and molecular modeling of these new DANAs have been discussed., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

The HIV-1 entry into host cells is a complex, multi-factors involved, and multi-step process. Especially, the attachment of HIV-1 envelope glycoprotein gp120 to the host cell receptor CD4 is the first key step during entry process, representing a promising antiviral therapeutic target. Among the HIV-1 attachment inhibitors blocking the interaction between gp120 and CD4 cells, BMS-378806 and NBD-556 are two representative small molecular chemical entities. Particularly, BMS-378806 and its derivatives are newly identified class of orally bioavailable HIV-1 inhibitors that interfere gp120-CD4 interaction. In this review, we focused on describing the structure-activity relationships (SARs), structural modifications, in vitro or even in vivo pharmacodynamics and pharmacokinetics of BMS-378806 and its analogues as HIV-1 gp120 attachment inhibitors. In addition, the brief SARs, structural modifications of NBD-556 and its derivatives targeting the "Phe-43 cavity" as CD4 mimics were also described., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Guided by crystal structures of HIV-1 RT/DAPY complex and molecular modeling studies, a series of novel [1,2,4]triazolo[1,5-a]pyrimidine derivatives were rationally designed via structure-based core refining approach, synthesized through the readily accessible synthetic methods and evaluated for their anti-HIV activities in MT-4 cells. Preliminary biological evaluation indicated that most of the compounds exhibited marked inhibitory activity against the wild-type HIV-1 IIIB. Particularly, compound 7n was the most potent inhibitor against wild-type and K103N/Y181C double resistant mutant strain of HIV-1, possessing EC50 values of 0.02 μM and 7.6 μM, respectively, which were much better than or similar to nevirapine (NVP, EC50 = 0.15 μM, 2.9 μM) and delavirdine (DLV, EC50 = 0.07 μM, >36 μM). Besides, some other compounds, 5b, 7c, 7e, 7f, and 7m, were also endowed with favorable anti-HIV-1 potency (EC50 = 0.07, 0.05, 0.05, 0.07, and 0.05 μM, respectively), which were better than or similar to those of NVP and DLV, suggesting a high potential to further develop this type of bridgehead nitrogen heterocycle as a novel class of NNRTIs with improved antiviral efficacy and resistance profile. The selected compound, 7i, was found moderately inhibitory towards RT (IC50 = 0.39 μM), which was higher than for ETV (IC50 = 0.56 μM). Preliminary structure-activity relationships (SARs) and molecular modeling of these new analogues were detailed in this manuscript., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

The cytotoxic activity of a new series of 2-(4'-chlorobenzyl)-5,6-disubstituted imidazo[2,1-b][1,3,4]thiadiazoles against different human and murine cancer cell lines is reported. Among the tested compounds, two derivatives namely 2-(4-chlorobenzyl)-6-(2-oxo-2H-chromen-3-yl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde 4i and 2-(4-chlorobenzyl)-6-(2-oxo-2H-chromen-3-yl)imidazo[2,1-b][1,3,4]thiadiazol-5-yl thiocyanate 5i emerged as the most potent against all the cell lines. To investigate the mechanism of action, we selected compounds 4i for cell cycle study, analysis of mitochondrial membrane potential and Annexin V-FITC flow cytometric analysis and DNA fragmentation assay. Results showed that 4i induced cytotoxicity by inducing apoptosis without arresting the cell cycle., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

This article reports the design, synthesis and antiviral evaluation of a new series of non-nucleoside reverse transcriptase inhibitors (NNRTIs). The basic skeleton of these target 18 molecules is diarylpyrimidine featuring a substituted amino group between the pyrimidine scaffold and the aryl wing. All of the new compounds have been characterized by spectra analysis. The entire target molecules were evaluated for their in vitro anti-HIV activity with controlling group of FDA approved drugs. Most of them showed good to potent activities against wild-type (WT) HIV-1 with IC50 values in the range of 0.0175-69.21 μM. 2-(4-Cyanophenylamino)-4-(2-cyanovinylphenylhydrazonomethyl)pyrimidine (1d) displayed potent anti-HIV-1 activity against WT HIV-1 with a selectivity index (SI) of 106367 and an IC50 value of 1.75 nM, which was 47 fold lower than that of AZT. Compound 1d also showed a broad-spectrum inhibitory activity, with an IC50 value of 5.33 μM and 5.05 μM against both HIV-1 double-mutated (K103N/Y181C) strain and HIV-2 strain, respectively. The preliminary structure-activity relationship (SAR) was also investigated. The binding modes with HIV-1 RT for both the wild type and mutant type have also been discussed., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Guided by crystal structures of HIV-1 RT/DAPY complex and molecular modeling studies, a series of novel DAPY derivatives were rationally designed, synthesized and evaluated for their anti-HIV activities. Among them, 16 compounds significantly inhibited HIV-1 IIIB replication with EC50 values lower than 66 nM. Particularly, compound 7a was the most potent inhibitor against HIV-1 wild-type and double RT mutant HIV-1 strain K103N/Y181C, with an EC50 value of 2.5 nM (SI = 13,740) and 0.33 μM (SI = 107), respectively. Unexpectedly, compound 8c was found to show moderate anti-HIV-2 potency (EC50 = 5.57 μM). Preliminary structure-activity relationships (SARs) and molecular modeling of these new analogues were also discussed in detail., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Novel clusters of 3,5-bis(benzylidene)-4-oxo-1-piperidinyl dimers 3-5 were evaluated against human Molt4/C8 and CEM T-lymphocytes and human HeLa cervix adenocarcinoma cells as well as murine L1210 leukemia neoplasms. Several of these compounds demonstrated IC50 values in the submicromolar and low micromolar range and compounds possessing 4-fluoro, 4-chloro and 3,4,5-trimethoxy substituents in the series 3 and 4 were identified as potent molecules. A heat map revealed the very high cytotoxic potencies of representative compounds against a number of additional leukemic and lymphoma cell lines and displayed greater toxicity to these cells than nonmalignant MCF10A and Hs-27 neoplasms. These dienones are more refractory to breast and prostate cancers. The evaluation of representative compounds in series 3-5 against a panel of human cancer cell lines revealed them to be potent cytotoxins with average IC50 values ranging from 0.05 to 8.51 μM. In particular, the most potent compound 4g demonstrated over 382-fold and 590-fold greater average cytotoxic potencies in this screen than the reference drugs, melphalan and 5-fluorouracil, respectively. A mode of action investigation of two representative compounds 3f and 4f indicated that they induce apoptosis which is due, at least in part, to the activation of caspase-3 and depolarization of the mitochondrial membrane potential., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

As a continuation of our efforts to discover and develop back-up analogs of DAPYs, novel substituted nitropyridine derivatives were designed via a structure-based core refining approach, synthesized and evaluated for their in vitro HIV-1 activity in MT-4 cells. Preliminary biological evaluation indicated that most of the compounds exhibited marked inhibitory activity against wild-type HIV-1 IIIB. Most notably, the compound 7b was identified as the most promising candidate in inhibiting HIV-1 replication with an EC50 value of 0.056 μM and a selective index (SI) of 1251, which were much better than those of NVP (EC₅₀ = 0.23 μM) and DLV (EC₅₀ = 0.51 μM). Some other compounds, 7k, 7c, 7j and 7e, were also endowed with a favorable anti-HIV-1 potency (EC₅₀ = 0.034, 0.11, 0.11 and 0.16 μM, respectively). Some antivirally active compounds also showed moderate inhibitory activity against RT. Preliminary structure-activity relationships (SARs) and molecular modeling of these new analogs provide valuable avenues for future molecular optimization., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

This paper reports the synthesis and antiviral evaluation of a series of non-nucleoside reverse transcriptase inhibitors (NNRTIs) that combine the peculiar structural features of diarylpyrimidine derivatives (DAPYs) and benzophenone derivatives (BPs). The DAPY derivatives bearing benzoyl or alkoxyl substitutes on the A-ring showed the inhibitory activity against wild-type HIV-1 at the cellular level within the range of EC50 values from micromolar to nanomolar. Among these compounds, 1u exhibited the most potent anti-HIV-1 activity (EC50 = 0.06 ± 0.01 μM, SI > 6260), which were about 1.8-fold more active than nevirapine (NVP) and delavirdine (DLV). In addition, the binding modes with HIV-1 RT and the preliminary SAR studies of these derivatives were also considered for further investigation., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

A new compound library that contained 20 hinged benzimidazole-coumarin hybrids and their β-d-ribofuranosides was established. The anti-hepatitis C virus (HCV) activity of all novel coumarin derivatives, which were obtained by use of organic synthetic methods, was tested. Two of these hybrids exhibited appealing EC50 values of as low as 3.0 and 5.5 μM. The best selectivity index was 14. The incorporation of a d-ribofuranose into the hinged hybrids provided the corresponding nucleosides with the β configuration, one of which inhibited HCV replication with an EC50 value of 20 μM. Additionally, the structure-activity relationship is elucidated on the basis of the functional groups that were attached to the nuclei of benzimidazole, coumarin, and ribofuranose of the hybrids., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)