Discovery of piperidin-4-yl-aminopyrimidine derivatives as potent non-nucleoside HIV-1 reverse transcriptase inhibitors

Development of diarylpyrimidine derivatives (& other heterocycles) as HIV-1 and WT RT inhibitors

Reverse transcriptase (RT) is an enzyme encoded by the genetic material of retroviruses. Viruses such as HIV and hepatitis B employ an enzyme reverse transcriptase (RT) to generate complementary DNA from the RNA template during reverse transcription. Thus, viruses replicate their genomes and proliferate within the host genome. In particular, researchers are concerned about the pathogenic viruses that cause numerous diseases through this mechanism. The retroviruses that cause diseases in humans include human immunodeficiency virus (HIV), which causes AIDS, and human T-cell lymphotropic virus I (HTLV-1), which causes leukemia. HIV has been the most devastating health problem for decades. The number of recorded HIV cases was found to be approximately 39 million worldwide in 2022. Acquired immune deficiency syndrome (AIDS), most devastating disease caused by HIV-1 needs potent antiretroviral therapy for treatment. Among the effective treatments for AIDS, NNRTIs are key drugs in highly active antiretroviral therapy (HAART). Heterocyclic small molecules play an important role in drug discovery for treatment of HIV-1 infection. Particularly, diarylpyrimidines class of drugs have shown promising activity. In this review, anti-HIV-1 activity and RT inhibitory activity of heterocycle small molecules focusing mostly on diarylpyrimidines was discussed. Furthermore, structure-activity relationship was discussed emphasizing most potent molecules.

Anti-Herpes Simplex Virus Type 1 Activity Evaluation of Natural Derived Phloroglucinol Derivatives and Their Molecular Mechanisms Study

HSV-1 is a common infection that can cause cold sores. In this study, the anti-HSV-1 virus activity of three series compounds A1-A9, B1-B12, C1-C22 was screened by MTT assay, qRT-PCR assay, Western blot assay and viruses' plaque assays. The results of MTT assay disclosed that phloroglucinol derivatives C2 and C3 effectively inhibited the death of HSV-1 infected vero cells with the CC50 values of C2 and C3 were 72.64 μmol/L and 32.62 μmol/L in HaCaT cells, 137.6 μmol/L and 48.55 μmol/L in Hela cells. The IC50 values of C3 in vero cells and Hela cells were 19.26 μmol/L and 22.98 μmol/L, respectively. In the qRT-PCR experiments, it showed that C2 and C3 effectively reduced the synthesis of HSV-1 early viral gene VP16 and late viral gene gD. The Western blot results showed that both C2 and C3 inhibited the expression of HSV-1 gD protein in a concentration-dependent manner. Lastly, viruses' plaque assay results showed that C2 and C3 inhibited the production of HSV-1 progeny virus in Hela cells and HaCaT cells in a concentration-dependent manner. Taken together, these results suggest that C2 and C3 are promising candidate that warrants further attention in the development of anti-HSV-1 drugs.

N-Phenyl-1-(phenylsulfonyl)-1H-1,2,4-triazol-3-amine as a New Class of HIV-1 Non-nucleoside Reverse Transcriptase Inhibitor

Highly active antiretroviral therapy (HAART) has revolutionized human immunodeficiency virus (HIV) healthcare, turning it from a terminal to a potentially chronic disease, although some patients can develop severe comorbidities. These include neurological complications, such as HIV-associated neurocognitive disorders (HAND), which result in cognitive and/or motor function symptoms. We now describe the discovery, synthesis, and evaluation of a new class of N-phenyl-1-(phenylsulfonyl)-1H-1,2,4-triazol-3-amine HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTI) aimed at avoiding HAND. The most promising molecule, 12126065, exhibited antiviral activity against wild-type HIV-1 in TZM cells (EC50 = 0.24 nM) with low in vitro cytotoxicity (CC50 = 4.8 μM) as well as retained activity against clinically relevant HIV mutants. 12126065 also demonstrated no in vivo acute or subacute toxicity, good in vivo brain penetration, and minimal neurotoxicity in mouse neurons up to 10 μM, with a 50% toxicity concentration (TC50) of >100 μM, well below its EC50.

Hybrids of delavirdine and piperdin-4-yl-aminopyrimidines (DPAPYs) as potent HIV-1 NNRTIs: Design, synthesis and biological activities

The hybrids of delavirdine and piperdin-4-yl-aminopyrimidine (DPAPYs) were designed from two excellent HIV-1 NNRTIs delavirdine and piperidin-4-yl-aminopyrimidine via molecular hybridization. The target compounds 4a-r were prepared and evaluated for their cellular anti-HIV activities and cytotoxicities as well as the inhibitory activities against HIV-1 reverse transcriptase (RT). All the newly synthesized compounds demonstrated moderate to excellent potency against wild-type (WT) HIV-1 with EC50 values in a range of 5.7 to 0.0086 μM and against RT with IC50 values ranging from 12.0 to 0.11 μM, indicating that the DPAPYs were specific RT inhibitors. Among all, 4d displayed the most potent activity against WT HIV-1 (EC50 = 8.6 nM, SI = 2151). Gratifyingly, it exhibited good to excellent potency against the single HIV-1 mutants L100I, K103N, Y181C, Y188L, E138K, as well as the double mutant F227L + V106A. Furthermore, the preliminary structure-activity relationships were summarized, molecular modeling was conducted to explore the binding mode of DPAPYs and HIV-1 RT, and their physicochemical properties were also predicted.

Druggability modification strategies of the diarylpyrimidine-type non-nucleoside reverse transcriptase inhibitors

Drug discovery of human immunodeficiency virus (HIV) is a hot field in medicinal chemistry community for many years. The diarylpyrimidines (DAPYs) are the second-generation non-nucleoside reverse transcriptase inhibitors (NNRTIs) targeting reverse transcriptase, playing a great irreplaceable role in HIV transcriptional therapy. However, fast-growing drug-resistant mutations as nonnegligible challenge are still unpredictably appeared in the clinical practice, leading to deactivate or reduce the existing drugs. In the last 20 years, more and more novel DAPY derivatives have developed with the purpose to counter the mutants. Nevertheless, most of them have dissatisfactory pharmacokinetics (PK) or poor antiviral activity toward resistant mutant strains. In this article, we will analyze the NNRTI derivatives with promising druggability, and summarize a series of druggability modification strategies to improve the antiviral activity, reduce toxicity and improve the PK properties in recent years. The prospects of DAPYs and the directions for future efforts will be discussed.

Development of non-nucleoside reverse transcriptase inhibitors (NNRTIs): our past twenty years

Human immunodeficiency virus (HIV) is the primary infectious agent of acquired immunodeficiency syndrome (AIDS), and non-nucleoside reverse transcriptase inhibitors (NNRTIs) are the cornerstone of HIV treatment. In the last 20 years, our medicinal chemistry group has made great strides in developing several distinct novel NNRTIs, including 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT), thio-dihydro-alkoxy-benzyl-oxopyrimidine (S-DABO), diaryltriazine (DATA), diarylpyrimidine (DAPY) analogues, and their hybrid derivatives. Application of integrated modern medicinal strategies, including structure-based drug design, fragment-based optimization, scaffold/fragment hopping, molecular/fragment hybridization, and bioisosterism, led to the development of several highly potent analogues for further evaluations. In this paper, we review the development of NNRTIs in the last two decades using the above optimization strategies, including their structure–activity relationships, molecular modeling, and their binding modes with HIV-1 reverse transcriptase (RT). Future directions and perspectives on the design and associated challenges are also discussed.

An Overview of Antiretroviral Agents for Treating HIV Infection in Paediatric Population

Paediatric Acquired ImmunoDeficiency Syndrome (AIDS) is a life-threatening and infectious disease in which the Human Immunodeficiency Virus (HIV) is mainly transmitted through Mother-To- Child Transmission (MTCT) during pregnancy, labour and delivery, or breastfeeding. This review provides an overview of the distinct therapeutic alternatives to abolish the systemic viral replication in paediatric HIV-1 infection. Numerous classes of antiretroviral agents have emerged as therapeutic tools for downregulation of different steps in the HIV replication process. These classes encompass Non- Nucleoside Analogue Reverse Transcriptase Inhibitors (NNRTIs), Nucleoside/Nucleotide Analogue Reverse Transcriptase Inhibitors (NRTIs/NtRTIs), INtegrase Inhibitors (INIs), Protease Inhibitors (PIs), and Entry Inhibitors (EIs). Co-administration of certain antiretroviral drugs with Pharmacokinetic Enhancers (PEs) may boost the effectiveness of the primary therapeutic agent. The combination of multiple antiretroviral drug regimens (Highly Active AntiRetroviral Therapy - HAART) is currently the standard therapeutic approach for HIV infection. So far, the use of HAART offers the best opportunity for prolonged and maximal viral suppression, and preservation of the immune system upon HIV infection. Still, the frequent administration of high doses of multiple drugs, their inefficient ability to reach the viral reservoirs in adequate doses, the development of drug resistance, and the lack of patient compliance compromise the complete HIV elimination. The development of nanotechnology-based drug delivery systems may enable targeted delivery of antiretroviral agents to inaccessible viral reservoir sites at therapeutic concentrations. In addition, the application of Computer-Aided Drug Design (CADD) approaches has provided valuable tools for the development of anti-HIV drug candidates with favourable pharmacodynamics and pharmacokinetic properties.

Multiple Machine Learning Comparisons of HIV Cell-based and Reverse Transcriptase Data Sets

The human immunodeficiency virus (HIV) causes over a million deaths every year and has a huge economic impact in many countries. The first class of drugs approved were nucleoside reverse transcriptase inhibitors. A newer generation of reverse transcriptase inhibitors have become susceptible to drug resistant strains of HIV, and hence, alternatives are urgently needed. We have recently pioneered the use of Bayesian machine learning to generate models with public data to identify new compounds for testing against different disease targets. The current study has used the NIAID ChemDB HIV, Opportunistic Infection and Tuberculosis Therapeutics Database for machine learning studies. We curated and cleaned data from HIV-1 wild-type cell-based and reverse transcriptase (RT) DNA polymerase inhibition assays. Compounds from this database with ≤1 μM HIV-1 RT DNA polymerase activity inhibition and cell-based HIV-1 inhibition are correlated (Pearson r = 0.44, n = 1137, p < 0.0001). Models were trained using multiple machine learning approaches (Bernoulli Naive Bayes, AdaBoost Decision Tree, Random Forest, support vector classification, k-Nearest Neighbors, and deep neural networks as well as consensus approaches) and then their predictive abilities were compared. Our comparison of different machine learning methods demonstrated that support vector classification, deep learning, and a consensus were generally comparable and not significantly different from each other using 5-fold cross validation and using 24 training and test set combinations. This study demonstrates findings in line with our previous studies for various targets that training and testing with multiple data sets does not demonstrate a significant difference between support vector machine and deep neural networks.

Design and synthesis of a novel series of non-nucleoside HIV-1 inhibitors bearing pyrimidine and N-substituted aromatic piperazine

A novel series of substituted piperazine-1-yl-pyrimidine derivatives were designed and synthesized as a new type of HIV-1 non-nucleoside inhibitors. Various N-substituted aromatic groups were incorporated into the piperazine ring through a simple and practical route to investigate the biological activity of these target compounds against wild-type and resistant strains of HIV-1. All of the target compounds were also evaluated as HIV-1 reverse transcriptase inhibitors in MT-4 cell cultures. The biological results showed that six of these compounds displayed inhibitory activities against the wild-type strain, among of which 7q and 7t were found to be the two most active analogues possessing EC₅₀ values of 31.50 μM and 3.36 μM, respectively. Molecular modeling studies of 7q provide valuable information for developing new anti-HIV-1 inhibitors.

Advances in diarylpyrimidines and related analogues as HIV-1 nonnucleoside reverse transcriptase inhibitors

HIV-1 nonnucleoside reverse transcriptase inhibitors (NNRTIs) have been playing an important role in the fight against acquired immunodeficiency syndrome (AIDS). Diarylpyrimidines (DAPYs) as the second generation NNRTIs, represented by etravirine (TMC125) and rilpivirine (TMC278), have attracted extensive attention due to their extraordinary potency, high specificity and low toxicity. However, the rapid emergence of drug-resistant virus strains and dissatisfactory pharmacokinetics of DAPYs present new challenges. In the past two decades, an increasing number of novel DAPY derivatives have emerged, which significantly enriched the structure-activity relationship of DAPYs. Studies of crystallography and molecular modeling have afforded a lot of useful information on structural requirements of NNRTIs, which contributes greatly to the improvement of their resistance profiles. In this review, we reviewed the discovery history and their evolution of DAPYs including their structural modification, derivatization and scaffold hopping in continuous pursuit of excellent anti-HIV drugs. And also, we discussed the prospect of DAPYs and the directions of future efforts.

Docking-based 3D-QSAR and pharmacophore studies on diarylpyrimidines as non-nucleoside inhibitors of HIV-1 reverse transcriptase

Diarylpyrimidines (DAPYs), a type of effective HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs), have been considered as one of the most successful agents for treating AIDS. A number of structurally diverse DAPYs have been designed and synthesized in the past decade, and most of them exhibited potent anti-HIV-1 activities; however, the structure-activity relationships of recently reported DAPYs and their pharmacophore features that interacted with HIV-1 reverse transcriptase (RT) remain to be studied. In the present study, molecular docking studies were first performed on three novel classes of DAPYs to study their binding pattern in the HIV-1 RT. Based on the docking conformations of these DAPYs, 3D-QSAR models were constructed using CoMSIA and Topomer CoMFA methods, and pharmacophore models were also built using distance comparison technique. All selected DAPYs presented preferred U- or L-shaped conformations while being docked into the non-nucleoside inhibitor-binding pocket of the HIV-1 RT. The best CoMSIA model exhibited powerful predictivity, with satisfactory statistical parameters such as a q² of 0.572, an r² of 0.952, and an [Formula: see text] of 0.728. Contour maps of the best CoMSIA model were in accordance with those of the Topomer CoMFA model, giving the insight into the feature requirements of DAPYs for the anti-HIV-1 activity. Three potential pharmacophore models were constructed, and each of them was consisted of five hypothesis features. All results suggested that the aromatic ring on the left wing of DAPYs and the central pyrimidine ring contained key pharmacophore features for the anti-HIV-1 activity, and also indicated that the right wing of DAPYs had potential for further structural modification to improve activity. Eight novel DAPY molecules with potential anti-HIV-1 activities were designed on the basis of the obtained results. The findings in this study might provide important information for further design and development of novel HIV-1 NNRTIs.

Novel HIV-1 Non-nucleoside Reverse Transcriptase Inhibitors: A Combinatorial Approach

Highly active antiretroviral therapy (HAART) is one of the most effective means for fighting against HIV-infection. HAART primarily targets HIV-1 reverse transcriptase (RT), and 14 of 28 compounds approved by the FDA as anti-HIV drugs act on this enzyme. HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) hold a special place among HIV RT inhibitors owing to their high specificity and unique mode of action. Nonetheless, these drugs show a tendency to decrease their efficacy due to high HIV-1 variability and formation of resistant virus strains tolerant to clinically applied HIV NNRTIs. A combinatorial approach based on varying substituents within various fragments of the parent molecule that results in development of highly potent compounds is one of the approaches aimed at designing novel HIV NNRTIs. Generation of HIV NNRTIs based on pyrimidine derivatives explicitly exemplifies this approach, which is discussed in this review.