Anti-HIV diarylpyrimidine–quinolone hybrids and their mode of action

Leveraging Ligand Affinity and Properties: Discovery of Novel Benzamide-Type Cereblon Binders for the Design of PROTACs

Immunomodulatory imide drugs (IMiDs) such as thalidomide, pomalidomide, and lenalidomide are the most common cereblon (CRBN) recruiters in proteolysis-targeting chimera (PROTAC) design. However, these CRBN ligands induce the degradation of IMiD neosubstrates and are inherently unstable, degrading hydrolytically under moderate conditions. In this work, we simultaneously optimized physiochemical properties, stability, on-target affinity, and off-target neosubstrate modulation features to develop novel nonphthalimide CRBN binders. These efforts led to the discovery of conformationally locked benzamide-type derivatives that replicate the interactions of the natural CRBN degron, exhibit enhanced chemical stability, and display a favorable selectivity profile in terms of neosubstrate recruitment. The utility of the most potent ligands was demonstrated by their transformation into potent degraders of BRD4 and HDAC6 that outperform previously described reference PROTACs. Together with their significantly decreased neomorphic ligase activity on IKZF1/3 and SALL4, these ligands provide opportunities for the design of highly selective and potent chemically inert proximity-inducing compounds.

Hybrid Molecules as Potential Drugs for the Treatment of HIV: Design and Applications

Human immunodeficiency virus (HIV) infection is a major problem for humanity because HIV is constantly changing and developing resistance to current drugs. This necessitates the development of new anti-HIV drugs that take new approaches to combat an ever-evolving virus. One of the promising alternatives to combination antiretroviral therapy (cART) is the molecular hybrid strategy, in which two or more pharmacophore units of bioactive scaffolds are combined into a single molecular structure. These hybrid structures have the potential to have higher efficacy and lower toxicity than their parent molecules. Given the potential advantages of the hybrid molecular approach, the development and synthesis of these compounds are of great importance in anti-HIV drug discovery. This review focuses on the recent development of hybrid compounds targeting integrase (IN), reverse transcriptase (RT), and protease (PR) proteins and provides a brief description of their chemical structures, structure–activity relationship, and binding mode.

Design and Synthesis of New Pyrimidine-Quinolone Hybrids as Novel hLDHA Inhibitors

A battery of novel pyrimidine-quinolone hybrids was designed by docking scaffold replacement as lactate dehydrogenase A (hLDHA) inhibitors. Structures with different linkers between the pyrimidine and quinolone scaffolds (10-21 and 24−31) were studied in silico, and those with the 2-aminophenylsulfide (U-shaped) and 4-aminophenylsulfide linkers (24−31) were finally selected. These new pyrimidine-quinolone hybrids (24−31)(a−c) were easily synthesized in good to excellent yields by a green catalyst-free microwave-assisted aromatic nucleophilic substitution reaction between 3-(((2/4-aminophenyl)thio)methyl)quinolin-2(1H)-ones 22/23(a−c) and 4-aryl-2-chloropyrimidines (1−4). The inhibitory activity against hLDHA of the synthesized hybrids was evaluated, resulting IC50 values of the U-shaped hybrids 24−27(a−c) much better than the ones of the 1,4-linked hybrids 28−31(a−c). From these results, a preliminary structure−activity relationship (SAR) was established, which enabled the design of novel 1,3-linked pyrimidine-quinolone hybrids (33−36)(a−c). Compounds 35(a−c), the most promising ones, were synthesized and evaluated, fitting the experimental results with the predictions from docking analysis. In this way, we obtained novel pyrimidine-quinolone hybrids (25a, 25b, and 35a) with good IC50 values (<20 μM) and developed a preliminary SAR.

HIV-1 Reverse Transcriptase/Integrase Dual Inhibitors: A Review of Recent Advances and Structure-activity Relationship Studies

The significant threat to humanity is HIV infection, and it is uncertain whether a definitive treatment or a safe HIV vaccine is. HIV-1 is continually evolving and resistant to commonly used HIV-resistant medications, presenting significant obstacles to HIV infection management. The drug resistance adds to the need for new anti-HIV drugs; it chooses ingenious approaches to fight the emerging virus. Highly Active Antiretroviral Therapy (HAART), a multi-target approach for specific therapies, has proved effective in AIDS treatment. Therefore, it is a dynamic system with high prescription tension, increased risk of medication reactions, and adverse effects, leading to poor compliance with patients. In the HIV-1 lifecycle, two critical enzymes with high structural and functional analogies are reverse transcriptase (RT) and integrase (IN), which can be interpreted as druggable targets for modern dual-purpose inhibitors. Designed multifunctional ligand (DML) is a new technique that recruited many targets to be achieved by one chemical individual. A single chemical entity that acts for multiple purposes can be much more successful than a complex multidrug program. The production of these multifunctional ligands as antiretroviral drugs is valued with the advantage that the viral-replication process may end in two or more phases. This analysis will discuss the RT-IN dual-inhibitory scaffolds' developments documented so far.

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.

Synthesis, Cytotoxicity, ADMET and Molecular Docking Studies of Some Quinoline-Pyrimidine Hybrid Compounds: 3-(2-Amino-6-arylpyrimidin-4- yl)-4-hydroxy-1-methylquinolin-2(1H)-ones

AIMS

Synthesis of 3-(2-amino-6-arylpyrimidin-4-yl)-4-hydroxy-1-methylquinolin-2(1H)-ones and estimation their anticancer activities on HepG2 and KB cancer lines.

BACKGROUND

Many derivatives of quinoline-2-on have been consider to synthesize and evaluate their biological properties by organic chemists due to their various biological effects, including antibacterial, antioxidant, anti-inflammatory, anticancer activities. Quinolinepyrimidine hybrid compounds exhibited various biological activities, such as antituberculosis, antibacterial, anticancer, antifungal, etc. The connection of 4-hydroxyquinoline-2-one with 2-amino-pyrimidine could initiate the new activities.

OBJECTIVE

α,β-Unsaturated ketones of 3-acetyl-4-hydroxy-N-methylquinolin-2-one were prepared. Novel 2-amino-6-aryl-4-(4'-hydroxy-Nmethylquinolin- 2'-on-3'-yl)pyrimidines have been synthesized by reaction of these corresponding α,β-unsaturated ketones with guanidine hydrochloride. Human hepatocellular carcinoma HepG2 and squamous cell carcinoma KB cancer lines were used for screening their cytotoxicity.

METHOD

3-Acetyl-4-hydroxy-N-methylquinolin-2-one was prepared from N-methylaniline and diethyl malonate. Reaction of (un)substituted benzaldehydes with this 4-hydroxyquinoline-2-one produced corresponding substituted α ,β-unsaturated ketones in the presence of piperidine as catalyst. 2-Amino-6-aryl-4-(4'-hydroxy-N-methylquinolin-2'-on-3'-yl)pyrimidines have been synthesized from these α,β-unsaturated ketones of 3-acetyl-4-hydroxy-N-methylquinolin-2-one by reaction of corresponding α ,β-unsaturated ketones with guanidine hydrochloride. All obtained pyrimidines were screened for anticancer activity using MTT bio-assay method.

RESULT

Seven substituted (E)-4-hydroxy-3-(3-(aryl)acryloyl)-1-methylquinolin-2(1H)-ones were prepared and converted to corresponding substituted 2-amino-6-aryl-4-(4'-hydroxy-N-methylquinolin-2'-on-3'-yl)pyrimidines with yields of 58-74%. All the synthesized pyrimidines were screened for their in vitro anticancer activity against human hepatocellular carcinoma HepG2 and squamous cell carcinoma KB cancer lines. Compounds 6b and 6e had the best activity in the series, with IC50 values equal to 1.32 and 1.33 μM, respectively. ADMET properties showed that compounds 6b, 6e, and 6f possessed the drug-likeness behavior. Cross-docking results indicated that residues GLN778(A), DT8(C), DT9(D), DA12(F), and DG13(F) in the binding pocket as potential ligand binding hot-spot residues for compounds 6b, 6e, and 6f.

CONCLUSION

New substituted 2-amino-6-aryl-4-(4'-hydroxy-N-methylquinolin-2'-on-3'-yl)pyrimidines were obtained and displayed significant inhibition against human hepatocellular carcinoma HepG2 and squamous cell carcinoma KB cancer lines.

Design and synthesis of novel desfluoroquinolone-aminopyrimidine hybrids as potent anti-MRSA agents with low hERG activity

Despite the fact that the introduction of a fluorine atom at the C-6 position has resulted in the evolution of fluoroquinolones, fluoroquinolone-induced cardiac toxicity has drawn considerable attention. In this context, desfluoroquinolone-based hybrids with involvement of C-7 aminopyrimidine functional group were designed and synthesized. The biological results showed majority of these hybrids still demonstrated potent anti-MRSA activity with MIC values between 0.38 and 1.5 μg/mL, despite the lack of the typical C-6 fluorine atom. Particularly, the most active B14 exhibited activities at submicromolar concentrations against a panel of MRSA strains including vancomycin-intermediate strains, levofloxacin-resistant isolates, and linezolid-resistant isolates, etc. As expected, it also displayed highly selective toxicity toward bacterial cells and low hERG inhibition. Further resistance development study indicated MRSA is unlikely to acquire resistance against B14. The docking study revealed that two hydrogen bonds were formed between the C-7 substituent and the surrounding DNA bases, which might contribute to overcome resistance by reducing the dependence on the magnesium-water bridge interactions with topoisomerase IV. These results indicate a promising strategy for developing new antibiotic quinolones to combat multidrug resistance and cardiotoxicity.

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.

4-Oxoquinoline Derivatives as Antivirals: A Ten Years Overview

4-Oxoquinoline derivatives constitute an important family of biologically important substances, associated with different bioactivities, which can be synthesized by different synthetic methods, allowing the design and preparation of libraries of substances with specific structural variations capable of modulating their pharmacological action. Over the last years, these substances have been extensively explored by the scientific community in efforts to develop new biologically active agents, with greater efficiency for the treatment of a variety of diseases. Viral infections have been one of the targets of these studies, although to a lesser extent than other diseases such as cancer and bacterial infections. Nevertheless, the literature provides examples that corroborate with the fact that these substances may act on different pharmacological targets in different viral pathogens. This review provides a compilation of some of the major studies published in recent years showing the discovery and/or development of new antiviral oxoquinoline agents, highlighting, whenever possible, their mechanisms of action.

Evolution of HIV-1 reverse transcriptase and integrase dual inhibitors: Recent advances and developments

HIV infection is a major challenge to mankind and a definitive cure or a viable vaccine for HIV is still elusive. HIV-1 is constantly evolving and developing resistant against clinically used anti-HIV drugs thus posing serious hurdles in the treatment of HIV infection. This prompts the need to developed new anti-HIV drugs; preferentially adopting intelligent ways to counteract an evolving virus. Highly Active Anti-Retroviral Therapy (HAART): a strategy involving multiple targeting through various drugs has proven beneficial in the management of AIDS. However, it is a complex regimen with high drug load, increased risk of drug interactions and adverse effects, which lead to poor patient compliance. Reverse transcriptase (RT) and Integrase (IN) are two pivotal enzymes in HIV-1 lifecycle with high structural and functional analogy to be perceived as drug-able targets for novel dual-purpose inhibitors. Designed multi-functional ligand (DML) is a modern strategy by which multiple targets can be exploited using a single chemical entity. A single chemical entity acting on multiple targets can be much more effective than a complex multi-drug regimen. The development of such multifunctional ligands is highly valued in anti-HIV drug discovery with the proposed advantage of being able to stop two or more stages of viral replication cycle. This review will encompass the evolution of the RT-IN dual inhibitory scaffolds reported so far and the contribution made by the leading research groups over the years in this field.

Quinolines and Quinolones as Antibacterial, Antifungal, Anti-virulence, Antiviral and Anti-parasitic Agents

Infective diseases have become health threat of a global proportion due to appearance and spread of microorganisms resistant to majority of therapeutics currently used for their treatment. Therefore, there is a constant need for development of new antimicrobial agents, as well as novel therapeutic strategies. Quinolines and quinolones, isolated from plants, animals, and microorganisms, have demonstrated numerous biological activities such as antimicrobial, insecticidal, anti-inflammatory, antiplatelet, and antitumor. For more than two centuries quinoline/quinolone moiety has been used as a scaffold for drug development and even today it represents an inexhaustible inspiration for design and development of novel semi-synthetic or synthetic agents exhibiting broad spectrum of bioactivities. The structural diversity of synthetized compounds provides high and selective activity attained through different mechanisms of action, as well as low toxicity on human cells. This review describes quinoline and quinolone derivatives with antibacterial, antifungal, anti-virulent, antiviral, and anti-parasitic activities with the focus on the last 10 years literature.

Fluoroquinolone-isatin hybrids and their biological activities

Hybridization of different pharmacophores from various bioactive substances into a single molecule is the potential weapon to prevent the drug resistance since this strategy can provide new leads with complimentary activities and/or multiple pharmacological targets. Fluoroquinolone and isatin are common pharmacophores, and their derivatives possess various biological activities. Obviously, hybridization of these two pharmacophores into one molecule may result in novel candidates with broader spectrum, higher efficiency, lower toxicity as well as multiple mechanisms of action. Therefore, fluoroquinolone-isatin hybrids have the potential for clinical deployment in the control and eradication of various diseases. This review covers the recent advances of fluoroquinolone-isatin hybrids as potential anti-bacterial, anti-tubercular, anti-viral and anti-cancer agents. The structure-activity relationship is also discussed to pave the way for the further rational development of this kind of hybrids.

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.

Synthesis, identification and in vitro biological evaluation of some novel quinoline incorporated 1,3-thiazinan-4-one derivatives

The present study describes the synthesis of two new series of 3-hydroxy-N-(4-oxo-2-phenyl-1,3-thiazinan-3-yl)-8-(trifluoromethyl)quinoline-2-carboxamide derivatives (4a-j) and 3-((7-chloroquinolin-4-ylamino)methyl)-2-phenyl-1,3-thiazinan-4-one derivatives (5a-7j). All the compounds were synthesized in moderate to good yield by one-pot three component cyclo-condensation reaction. The newly synthesized compounds were characterized by FT-IR, ¹H, ¹³C NMR and elemental analysis. The compounds were screened for their in vitro antibacterial activity against a panel of pathogenic bacterial strains, antitubercular activity against Mycobacterium tuberculosis H₃₇Rv and also for their in vitro antimalarial activity against Plasmodium falciparum. Among the synthesized compounds two of them (4f and 5f) showed excellent antibacterial activity against C. tetani at 15.6μg/mL. Some of them exhibited excellent antitubercular (4f &5f) and good antimalarial (4f, 5f &6f) activity compared with the first line drugs.

Advances in rationally designed dual inhibitors of HIV-1 reverse transcriptase and integrase

Reverse transcriptase (RT) and integrase (IN) are two indispensable enzymes in human immunodeficiency virus type 1 (HIV-1) replication. RT is responsible for the transformation of the single-stranded RNA viral genome into double-stranded DNA, and IN catalyzes the integration of viral DNA into the host DNA. Although highly active antiretroviral therapy (HAART) combining nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs/NtRTIs) with nonnucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs) could suppress successfully HIV viral load and reduce evidently the mortality of HIV infected people, it involves the difficulty of perfect adherence, and other drawbacks such as viral rebound, toxicities and multi-drug resistances. Recently, rational drug design has become a dominant technique for the development of multi-target drugs. And the rationally designed dual inhibitors of HIV-1 RT and IN have become a hot topic of anti-HIV research. In this review, the advances in rationally designed dual inhibitors of HIV-1 RT and IN were summarized, including structurally diverse inhibitors, their structure-activity relationship (SAR) studies as well as binding mode analysis.