Targeting the entrance channel of NNIBP: Discovery of diarylnicotinamide 1,4-disubstituted 1,2,3-triazoles as novel HIV-1 NNRTIs with high potency against wild-type and E138K mutant virus

Deciphering the enigmas of non-nucleoside reverse transcriptase inhibitors (NNRTIs): A medicinal chemistry expedition towards combating HIV drug resistance

The pivotal involvement of reverse transcriptase activity in the pathogenesis of the progressive HIV virus has stimulated gradual advancements in drug discovery initiatives spanning three decades. Consequently, nonnucleoside reverse transcriptase inhibitors (NNRTIs) have emerged as a preeminent category of therapeutic agents for HIV management. Academic institutions and pharmaceutical companies have developed numerous NNRTIs, an essential component of antiretroviral therapy. Six NNRTIs have received Food and Drug Administration approval and are widely used in clinical practice, significantly improving the quality of HIV patients. However, the rapid emergence of drug resistance has limited the effectiveness of these medications, underscoring the necessity for perpetual research and development of novel therapeutic alternatives. To supplement the existing literatures on NNRTIs, a comprehensive review has been compiled to synthesize this extensive dataset into a comprehensible format for the medicinal chemistry community. In this review, a thorough investigation and meticulous analysis were conducted on the progressions achieved in NNRTIs within the past 8 years (2016-2023), and the experiences and insights gained in the development of inhibitors with varying chemical structures were also summarized. The provision of a crucial point of reference for the development of wide-ranging anti-HIV medications is anticipated.

Drug Discovery and Exploration of Heterocycles for the Development of Anti-HIV Agents

It is a known fact that HIV infection remains a serious public health problem throughout the world, and the need to constantly develop new antiretroviral drugs to combat HIV emerges from the fact that repetitive mutations occurring in viral enzymes make this virus resistant to antiretroviral drugs. This resistance causes failure of treatment, and hence, for many years, extensive research has been to discover newer possibilities for fighting this disease at a molecular level, along with many long-standing and expensive clinical trials. Many scientific research programs have either been discarded or unsuccessful. However, the research has not stopped, and in the process, many heterocyclic scaffolds have been used to build up novel drug molecules to combat this disease. A literature survey reveals that many heterocycles have been explored and were found to be very useful in treating different types of viral infections. This concise and rigorous literature explains the journey and highlights the various strategies to develop new anti-HIV drug candidates.

Design, Synthesis and Application of 1,4-disubstituted 1,2,3-triazole Based Chemosensors: A Promising Avenue

The 1,2,3-triazole-based chemosensors, synthesized through Cu(I)-catalyzed azide-alkyne cycloaddition via 'click chemistry', offer a straightforward yet highly effective method for detecting metal cations and anions with remarkable accuracy, selectivity and sensitivity, making them invaluable across various fields such as chemistry, pharmacology, environmental science and biology. The selective recognition of these ions is crucial due to their significant roles in biological and physiological processes, where even slight concentration variations can have major consequences. The article reviews literature from 2017 to 2024, highlighting advancements in the synthesis of 1,2,3-triazole-based ligands and their application (along with sensing mechanism) for detection of various ions causing health and environmental hazards. The detection aspects have been discussed sequentially for the transition-, inner transition-, and the metals from the s or p block of the periodic table.

One-pot synthesis of tetrahydropyrimidinecarboxamides enabling in vitro anticancer activity: a combinative study with clinically relevant brain-penetrant drugs

In this study, we describe a one-pot three-component synthesis of bioactive tetrahydopyrimidinecarboxamide derivatives employing lanthanum triflate as a catalyst. Out of the synthesized compounds, 4f had the most potent anti-cancer activity and impeded cell cycle progression effectively. Anti-cancer bioactivity was observed in 4f against liver, breast, and lung cancers as well as primary patient-derived glioblastoma cell lines. Compound 4f effectively inhibited the 3D neurosphere formation in primary patient-derived glioma stem cells. Specifically, 4f exhibited synergistic cytotoxicity with the EGFR inhibitor that is the clinical epidermal growth factor receptor inhibitor osimertinib. 4f does not exhibit anti-kinase activity and is cytostatic in nature, and further work is needed to understand the true molecular target of 4f and its derivatives. Through our current work, we establish a promising tetrahydopyrimidinecarboxamide-based lead compound with anti-cancer activity, which may exhibit potent anti-cancer activity in combination with specific clinically relevant small molecule kinase inhibitors.

Synthesis of triazole AD-1 derivatives and its mechanism of mediating DNA damage of ROS in lung cancer cells

Based on the significant biological activities and the remarkable physical and chemical properties of 1H-1,2,3-triazole pharmacophore, we herein adopted the strategy of click chemistry to combine the triazole fragment and the unique scaffold of 25-OCH3-PPD (AD-1) to design a series of potent compounds inducing apoptosis and DNA damage. The anti-proliferative effect was verified by MTT assay and colony formation assay. DNA double-stand breaks (DSBs) were obtained by observing the nuclear focus formation and the protein expression of γ-H2AX. Cell cycle arrest was evaluated by the cycle-related proteins such as CDK2, CDK4, CDK6, Cyclin D1 and P21. Apoptosis was assessed by flow cytometry, mitochondrial membrane potential (MMP) detection and the expression of apoptosis-related proteins. Reactive oxygen species (ROS) generation was measured with 2', 7'-dichlorofluorescein diacetate (DCFH-DA) staining. According to SAR analysis, the most potent compound 6a exhibited great inhibitory effect against A549 cells, which IC50 value of 2.84 ± 0.68 μM. Furthermore, 6a remarkably induced DNA damage, cell cycle arrest and apoptosis in A549 cells. 6a treatment increased the levels of ROS. Network pharmacology and molecular docking predicted the potential signaling pathways and ligand-receptor interactions, and the results of western blotting showed that 6a inhibited the PI3K/Akt/Bcl-2 signaling pathway by decreasing PI3K and Bcl-2 and total level of Akt expression, while Bax and Cyt c were increasing in 6a-treated A549 cells. As mentioned above, 6a has a potent inhibitory effect in A549 cells through induction of DNA damage, apoptosis via ROS generation and modulation of PI3K/Akt/Bcl-2 signaling pathway.

A Literature Review Focusing on the Antiviral Activity of [1,2,4] and [1,2,3]-triazoles

Out of a variety of heterocycles, triazole scaffolds have been shown to play a significant part in a wide array of biological functions. Many drug compounds containing a triazole moiety with important antimicrobial, anticancer and antidepressant properties have been commercialized. In addition, the triazole scaffold exhibits remarkable antiviral activity either incorporated into nucleoside analogs or non-nucleosides. Many synthetic techniques have been produced by scientists around the world as a result of their wide-ranging biological function. In this review, we have tried to summarize new synthetic methods produced by diverse research groups as well as provide a comprehensive description of the function of [1,2,4] and [1,2,3]-triazole derivatives as antiviral agents. Antiviral triazole compounds have been shown to target a wide variety of molecular proteins. In addition, several strains of viruses, including the human immunodeficiency virus, SARS virus, hepatitis B and C viruses, influenza virus, Hantavirus, and herpes virus, were discovered to be susceptible to triazole derivatives. This review article covered the reports for antiviral activity of both 1,2,3- and 1,2,4-triazole moieties up to 2022.

Meldrum-Based-1H-1,2,3-Triazoles as Antidiabetic Agents: Synthesis, In Vitro α-Glucosidase Inhibition Activity, Molecular Docking Studies, and In Silico Approach

A series of novel alkyl derivatives (2-5a,b) and 1H-1,2,3-triazole analogues (7a-k) of Meldrum's acid were synthesized in a highly effective way by using "click" chemistry and screened for in vitro α-glucosidase inhibitory activity to examine their antidiabetic potential. ¹H NMR, ¹³C-NMR, and high-resolution electrospray ionization mass spectra (HR-ESI-MS) were used to analyze each of the newly synthesized compounds. Interestingly, these compounds demonstrated high to moderate α-glucosidase inhibitory potency having an IC₅₀ range of 4.63-80.21 μM. Among these derivatives, compound 7i showed extraordinary inhibitory activity and was discovered to be several times more potent than the parent compound Meldrum (1) and the standard drug acarbose. Later, molecular docking was performed to understand the binding mode and the binding strength of all the compounds with the target enzyme, which revealed that all compounds are well fitted in the active site of α-glucosidase. To further ascertain the structure of compounds, suitable X-ray single crystals of compounds 5a, 7a, and 7h were developed and studied. The current investigation has shown that combining 1H-1,2,3-triazole with the Meldrum moiety is beneficial. Furthermore, this is the first time that the aforementioned activity of these compounds has been reported.

Novel Pyrano[3,2-c]quinoline-1,2,3-triazole Hybrids as Potential Anti-Diabetic Agents: In Vitro α-Glucosidase Inhibition, Kinetic, and Molecular Dynamics Simulation

In this study, a novel series of pyrano[3,2-c]quinoline-1,2,3-triazole hybrids 8a-o were synthesized and evaluated against the α-glucosidase enzyme. All compounds showed significant in vitro inhibitory activity (IC₅₀ values of 1.19 ± 0.05 to 20.01 ± 0.02 μM) compared to the standard drug acarbose (IC₅₀ = 750.0 μM). Among them, 2-amino-4-(3-((1-benzyl-1H-1,2,3-triazol-4-yl)methoxy)phenyl)-5-oxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carbonitrile (compound 8k) demonstrated the best inhibitory effect toward α-glucosidase (IC₅₀ = 1.19 ± 0.05 μM) with a competitive pattern of inhibition. Since compound 8k was synthesized as a racemic mixture, molecular docking and dynamics simulations were performed on R- and S-enantiomers of compound 8k. Based on the molecular docking results, both R- and S-enantiomers of compound 8k displayed significant interactions with key residues including catalytic triad (Asp214, Glu276, and Asp349) in the enzyme active site. However, an in silico study indicated that S- and R-enantiomers were inversely located in the enzyme active site. The R-enantiomer formed a more stable complex with a higher binding affinity to the active site of α-glucosidase than that of the S- enantiomer. The benzyl ring in the most stable complex ((R)-compound 8k) was located in the bottom of the binding site and interacted with the enzyme active site, while the pyrano[3,2-c]quinoline moiety occupied the high solvent accessible entrance of the active site. Thus, the synthesized pyrano[3,2-c]quinoline-1,2,3-triazole hybrids seem to be promising scaffolds for the development of novel α-glucosidase inhibitors.

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.

Insight into non-nucleoside triazole-based systems as viral polymerases inhibitors

Viruses have been recognized as the etiological agents responsible for many pathological conditions ranging from asymptomatic infections to serious diseases, even leading to death. For this reason, many efforts have been made to identify selective viral targets with the aim of developing efficient therapeutic strategies, devoid of drug-resistance issues. Considering their crucial role in the viral life cycle, polymerases are very attractive targets. Among the classes of compounds explored as viral polymerases inhibitors, here we present an overview of non-nucleoside triazole-based compounds identified in the last fifteen years. Furthermore, the structure-activity relationships (SAR) of the different chemical entities are described in order to highlight the key chemical features required for the development of effective antiviral agents.

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.

Discovery of New Boswellic Acid Hybrid 1H-1,2,3-Triazoles for Diabetic Management: In Vitro and In Silico Studies

A series of 24 new 1H-1,2,3-triazole hybrids of 3-O-acetyl-11-keto-β-boswellic acid (β-AKBA (1)) and 11-keto-β-boswellic acid (β-KBA (2)) was designed and synthesized by employing "click" chemistry in a highly efficient manner. The 1,3-dipolar cycloaddition reaction between β-AKBA-propargyl ester intermediate 3 or β-KBA-propargyl ester intermediate 4 with substituted aromatic azides 5a-5k in the presence of copper iodide (CuI) and Hünig's base furnished the desired products-1H-1,2,3-triazole hybrids of β-AKBA (6a-6k) and β-KBA (7a-7k)-in high yields. All new synthesized compounds were characterized by ¹H-, ¹³C-NMR spectroscopy, and HR-ESI-MS spectrometry. Furthermore, their α-glucosidase-inhibitory activity was evaluated in vitro. Interestingly, the results obtained from the α-glucosidase-inhibitory assay revealed that all the synthesized derivatives are highly potent inhibitors, with IC₅₀ values ranging from 0.22 to 5.32 µM. Among all the compounds, 6f, 7h, 6j, 6h, 6g, 6c, 6k, 7g, and 7k exhibited exceptional inhibitory potency and were found to be several times more potent than the parent compounds 1 and 2, as well as standard acarbose. Kinetic studies of compounds 6g and 7h exhibited competitive and mixed types of inhibition, with ki values of 0.84 ± 0.007 and 1.18 ± 0.0012 µM, respectively. Molecular docking was carried out to investigate the binding modes of these compounds with α-glucosidase. The molecular docking interactions indicated that that all compounds are well fitted in the active site of α-glucosidase, where His280, Gln279, Asp215, His351, Arg442, and Arg315 mainly stabilize the binding of these compounds. The current study demonstrates the usefulness of incorporating a 1H-1,2,3-triazole moiety into the medicinally fascinating boswellic acids skeleton.

A minireview of 1,2,3-triazole hybrids with O-heterocycles as leads in medicinal chemistry

Over the past few decades, the dynamic progress in the synthesis and screening of heterocyclic compounds against various targets has made a significant contribution in the field of medicinal chemistry. Among the wide array of heterocyclic compounds, triazole moiety has attracted the attention of researchers owing to its vast therapeutic potential and easy preparation via copper and ruthenium-catalyzed azide-alkyne cycloaddition reactions. Triazole skeletons are found as major structural components in a different class of drugs possessing diverse pharmacological profiles including anti-cancer, anti-bacterial, anti-fungal, anti-viral, anti-oxidant, anti-inflammatory, anti-diabetic, anti-tubercular, and anti-depressant among various others. Furthermore, in the past few years, a significantly large number of triazole hybrids were synthesized with various heterocyclic moieties in order to gain the added advantage of the improved pharmacological profile, overcoming the multiple drug resistance and reduced toxicity from molecular hybridization. Among these synthesized triazole hybrids, many compounds are available commercially and used for treating different infections/disorders like tazobactam and cefatrizine as potent anti-bacterial agents while isavuconazole and ravuconazole as anti-fungal activities to name a few. In this review, we will summarize the biological activities of various 1,2,3-triazole hybrids with copious oxygen-containing heterocycles as lead compounds in medicinal chemistry. This review will be very helpful for researchers working in the field of molecular modeling, drug design and development, and medicinal chemistry.

Lead/Drug Discovery from Natural Resources

Natural products and their derivatives have been shown to be effective drug candidates against various diseases for many years. Over a long period of time, nature has produced an abundant and prosperous source pool for novel therapeutic agents with distinctive structures. Major natural-product-based drugs approved for clinical use include anti-infectives and anticancer agents. This paper will review some natural-product-related potent anticancer, anti-HIV, antibacterial and antimalarial drugs or lead compounds mainly discovered from 2016 to 2022. Structurally typical marine bioactive products are also included. Molecular modeling, machine learning, bioinformatics and other computer-assisted techniques that are very important in narrowing down bioactive core structural scaffolds and helping to design new structures to fight against key disease-associated molecular targets based on available natural products are considered and briefly reviewed.

New 1,2,3-triazole linked ciprofloxacin-chalcones induce DNA damage by inhibiting human topoisomerase I& II and tubulin polymerization

A series of novel 1,2,3-triazole-linked ciprofloxacin-chalcones 4a-j were synthesised as potential anticancer agents. Hybrids 4a-j exhibited remarkable anti-proliferative activity against colon cancer cells. Compounds 4a-j displayed IC₅₀s ranged from 2.53-8.67 µM, 8.67-62.47 µM, and 4.19-24.37 µM for HCT116, HT29, and Caco-2 cells; respectively, whereas the doxorubicin, showed IC₅₀ values of 1.22, 0.88, and 4.15 µM. Compounds 4a, 4b, 4e, 4i, and 4j were the most potent against HCT116 with IC₅₀ values of 3.57, 4.81, 4.32, 4.87, and 2.53 µM, respectively, compared to doxorubicin (IC₅₀ = 1.22 µM). Also, hybrids 4a, 4b, 4e, 4i, and 4j exhibited remarkable inhibitory activities against topoisomerase I, II, and tubulin polymerisation. They increased the protein expression level of γH2AX, indicating DNA damage, and arrested HCT116 in G2/M phase, possibly through the ATR/CHK1/Cdc25C pathway. Thus, the novel ciprofloxacin hybrids could be exploited as potential leads for further investigation as novel anticancer medicines to fight colorectal carcinoma.

Design of the naphthyl-diarylpyrimidines as potent non-nucleoside reverse transcriptase inhibitors (NNRTIs) via structure-based extension into the entrance channel

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 EC₅₀ 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.

1,2,3-Triazole hybrids as anticancer agents: A review

Despite the advancements in the development of anticancer agents, more effective and safer anticancer drugs still need to be developed as the current agents cause unwanted side effects and many patients have become drug resistant. 1,2,3-Triazoles, due to their remarkable biological potential, have received considerable attention in drug discovery for the development of anticancer agents. The present review article presents an overview of the recent advances in 1,2,3-triazole hybrids with anticancer potential over the last 2 years, their chemical structures, structure-activity relationships, and mechanisms of action, as well as insights into the docking studies.

Structure-Based Design and Discovery of Pyridyl-Bearing Fused Bicyclic HIV-1 Inhibitors: Synthesis, Biological Characterization, and Molecular Modeling Studies

Two series of new pyridyl-bearing fused bicyclic analogues designed to target the dual-tolerant regions of the non-nucleoside reverse transcriptase inhibitor (NNRTI)-binding pocket were synthesized and evaluated for their anti-HIV activities. Several compounds, such as 6, 14, 15, 21, 30, and 33, were found to be potent inhibitors against the wild-type (WT) HIV-1 strain or multiple NNRTI-resistant strains at low nanomolar levels. Detailed structure-activity relationships were obtained by utilizing the variation of moieties within the corresponding pharmacophores. In vitro metabolic stability profiles and some drug-like properties of selected compounds were assessed, furnishing the preliminary structure-metabolic stability relationships. Furthermore, molecular modeling studies elucidated the binding modes of compounds 6, 15, 21, and 30 in the binding pocket of WT, E138K, K103N, or Y181C HIV-1 RTs. These promising compounds can be used as lead compounds and warrant further structural optimization to yield more active HIV-1 inhibitors.

Chemical space exploration of novel naphthyl-carboxamide-diarylpyrimidine derivatives with potent anti-HIV-1 activity

Fifteen naphthyl-carboxamide-DAPYs were generated to explore chemical space in reverse transcriptase (RT) binding site via lead optimization strategy. They displayed up to single-digit nanomolar activity against wild-type (WT) and rilpivirine-associated resistant mutant E138K viruses, as well as potent inhibitory ability toward the RT enzyme. Compound a1 showed exceptionally inhibitory effects with an EC₅₀ value of 3.7 nM against HIV-1 wt strain, and an EC₅₀ of 11 nM targeting mutant E138K. The structure-activity relationships (SARs) of the newly obtained DAPYs were also investigated. Molecular docking analysis elucidated the biological activity and offered a structural insight for follow-up research.

Design, synthesis, and evaluation of "dual-site"-binding diarylpyrimidines targeting both NNIBP and the NNRTI adjacent site of the HIV-1 reverse transcriptase

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 EC₅₀ values ranging from 2.45 nM to 5.36 nM, and 14c (EC₅₀ = 2.45 nM) proved to be the most promising inhibitor. Of note, 14c exhibited potent activity against the single mutant strain E138K (EC₅₀ = 10.6 nM), being comparable with ETR (EC₅₀ = 9.80 nM) and 3.5-fold more potent than that of compound 7 (EC₅₀ = 37.3 nM). Moreover, 14c acted as a classical NNRTI with high affinity for WT HIV-1 RT (IC₅₀ = 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.

1,2,3-Triazole hybrids with anti-HIV-1 activity

The human immunodeficiency virus type 1 (HIV-1) is the major etiological agent responsible for the acquired immunodeficiency syndrome (AIDS), which is a serious infectious disease and remains one of the most prevalent problems at present. Currently, combined antiretroviral therapy is the primary modality for the treatment and management of HIV/AIDS, but the long-term use can result in major drawbacks such as the development of multidrug-resistant viruses and multiple side effects. 1,2,3-Triazole is the common framework in the development of new drugs, and its derivatives have the potential to inhibit various HIV-1 enzymes such as reverse transcriptase, integrase, and protease, consequently possessing a potential anti-HIV-1 activity. This review covers the recent advances regarding the 1,2,3-triazole hybrids with potential anti-HIV-1 activity; it focuses on the chemical structures, structure-activity relationship, and mechanisms of action, covering articles published from 2010 to 2020.

Discovery of potential dual-target prodrugs of HIV-1 reverse transcriptase and nucleocapsid protein 7

In the present work, we described the design, synthesis and biological evaluation of a novel series of potential dual-target prodrugs targeting the HIV-1 reverse transcriptase (RT) and nucleocapsid protein 7 (NCp7) simultaneously. Among them, the most effective compound 7c was found to inhibit HIV-1 wild-type (WT) strain at double-digit nanomolar concentration (EC₅₀ = 42 nM) in MT-4 cells, and sub-micromole (EC₅₀ = 0.308 μM) to inhibit HIV-1 NL4-3 strain in TZM-bl cells. This is a significant improvement over the parent drug MT. In addition, it showed moderate inhibitory potency (EC₅₀ = 1.329 μM) against the HIV-1 K103N/Y181C double mutant strain (MT-4 cells). The metabolic stability in human plasma of compound 7c indicated that it can release the active forms of the parent drugs MT and AZT in a linear time-independent manner and turn out to be a potential prodrug.

Structure-Activity Relationship Exploration of NNIBP Tolerant Region I Leads to Potent HIV-1 NNRTIs

Previous efforts in our lab have led to the development of human immunodeficiency virus type 1 (HIV-1) non-nucleoside reverse transcriptase inhibitor (NNRTI) thiophene[3,2-d]pyrimidine compound 1 (K-5a2) with promising activity against wild-type and mutant HIV-1 strains. In this work, a series of novel diarylpyrimidines derivatives carrying a structurally diverse motif at the right wing of the lead K-5a2 was designed and synthesized as potential anti-HIV-1 agents. The results demonstrated that 8a yielded exceptionally potent activity against HIV-1 wild-type (50% effective concentration (EC₅₀) = 3.30 nM) and mutant strain RES056 (EC₅₀ = 22.6 nM) in MT-4 cells; in the reverse transcriptase inhibitory assay, 8a (half maximal inhibitory concentration (IC₅₀) = 0.028 μM) was remarkably superior to that of K-5a2 (IC₅₀ = 0.300 μM) and comparable to that of etravirine (ETR; IC₅₀ = 0.011 μM). Notably, 8a exhibited better druggability than that of K-5a2, including significantly reduced CYP enzymatic inhibitory activity (IC₅₀ > 50 μM), lower human ether-à-go-go related gene (hERG) inhibition (IC₅₀ > 30 μM), and improved metabolic stability (short half-life, T_1/2 = 77.5 min) in vitro.

New N-phenylacetamide-linked 1,2,3-triazole-tethered coumarin conjugates: Synthesis, bioevaluation, and molecular docking study

A series of new 1,2,3-triazole-tethered coumarin conjugates linked by N-phenylacetamide was efficiently synthesized via the click chemistry approach in excellent yields. The synthesized conjugates were evaluated for their in vitro antifungal and antioxidant activities. Antifungal activity determination was carried out against fungal strains such as Candida albicans, Fusarium oxysporum, Aspergillus flavus, Aspergillus niger and Cryptococcus neoformans. Compounds 7b, 7d, 7e, 8b and 8e displayed higher potency than the standard drug miconazole, with lower minimum inhibitory concentration values. Also, compound 7a exhibited potential radical scavenging activity as compared with the standard antioxidant butylated hydroxytoluene. In addition, a molecular docking study of the newly synthesized compounds was carried out, and the results showed a good binding mode at the active site of the fungal (C. albicans) P450 cytochrome lanosterol 14α-demethylase enzyme. Furthermore, the synthesized compounds were also tested for ADME properties, and they demonstrated potential as good candidates for oral drugs.

Cu(II)-Hydrazide Coordination Compound Supported on Silica Gel as an Efficient and Recyclable Heterogeneous Catalyst for Green Click Synthesis of β-Hydroxy-1,2,3-triazoles in Water

A hydrazone ligand, (E)-6-(2-((2-hydroxynaphthalen-1-yl)methylene)hydrazinyl)nicotinohydrazide (H₂L), was synthesized and characterized by spectroscopic methods. The reaction of H₂L with CuCl₂·2H₂O in methanol gave Cu(II) coordination compound, [Cu(HL')(Cl)]·CH₃OH (1), which was characterized by elemental analysis and spectroscopic methods (Fourier transform infrared (FT-IR) and UV-vis). The structure of 1 was also determined by single-crystal X-ray analysis. Structural studies confirmed the formation of esteric group during the synthesis of 1. Compound 1 was immobilized on 3-aminopropyltriethoxysilane (APTS)-functionalized silica gel through the amidification reaction and the obtained heterogeneous coordination compound was utilized as a catalyst for the three-component azide-epoxide-alkyne cycloaddition reaction in water as a green solvent. The structural properties of the heterogeneous catalyst were characterized by a combination of FT-IR, UV-vis, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS) analyses. The effect of the amount of catalyst and temperature on the cycloaddition reaction was studied, and the obtained 1,2,3-triazoles were characterized by spectroscopic studies and single-crystal X-ray analysis. The catalytic investigations revealed that this catalytic system has high activity in the synthesis of β-hydroxy-1,2,3-triazoles. It was also found that the aromatic and aliphatic substituents on the alkyne and epoxide together with the reaction temperature have considerable effects on the activity and regioselectivity of this catalytic system.

Molecular Hybridization-Inspired Optimization of Diarylbenzopyrimidines as HIV-1 Nonnucleoside Reverse Transcriptase Inhibitors with Improved Activity against K103N and E138K Mutants and Pharmacokinetic Profiles

Molecular hybridization is a powerful strategy in drug discovery. A series of novel diarylbenzopyrimidine (DABP) analogues were developed by the hybridization of FDA-approved drugs etravirine (ETR) and efavirenz (EFV) as potential HIV-1 nonnucleoside reverse transcriptase inhibitors (NNRTIs). Substituent modifications resulted in the identification of new DABPs with the combination of the strengths of the two drugs, especially compound 12d, which showed promising activity toward the EFV-resistant K103N mutant. 12d also had a favorable pharmacokinetic (PK) profile with liver microsome clearances of 14.4 μL/min/mg (human) and 33.2 μL/min/mg (rat) and an oral bioavailability of 15.5% in rat. However, its activity against the E138K mutant was still unsatisfactory; E138K is the most prevalent NNRTI resistance-associated mutant in ETR treatment. Further optimizations resulted in a highly potent compound (12z) with no substituents on the phenyl ring and a 2-methyl-6-nitro substitution pattern on the 4-cyanovinyl-2,6-disubstitued phenyl motif. The antiviral activity of this compound was much higher than those of ETR and EFV against the WT, E138K, and K103N variants (EC₅₀ = 3.4, 4.3, and 3.6 nM, respectively), and the cytotoxicity was decreased while the selectivity index (SI) was increased. In particular, this compound exhibited acceptable intrinsic liver microsome stability (human, 34.5 μL/min/mg; rat, 33.2 μL/min/mg) and maintained the good PK profile of its parent compound EFV and showed an oral bioavailability of 16.5% in rat. Molecular docking and structure-activity relationship (SAR) analysis provided further insights into the binding of the DABPs with HIV-1 reverse transcriptase and provided a deeper understanding of the key structural features responsible for their interactions.