Synthesis and Biological Evaluation of a Series of 2-((1-substituted-1H-1,2,3-triazol-4-yl)methylthio)-6-(naphthalen-1-ylmethyl)pyrimidin-4(3H)-one As Potential HIV-1 Inhibitors

An Amazing 30-Year Journey around the DABO Family: A Medicinal Chemistry Lesson on a Versatile Class of Non-nucleoside HIV-1 Reverse Transcriptase Inhibitors

Since the emergence of AIDS, the non-nucleoside HIV-1 RT inhibitors (NNRTIs) have attracted the attention of scientists and clinicians due to their high potency and specificity combined with low toxicity. 3,4-Dihydro-2-alkoxy-6-benzyl-4-oxopyrimidines (DABOs) are a family of NNRTIs described since 1992, and the best members among S-, NH-, and N,N-DABOs showed high anti-HIV-1 potency in both cellular and enzymatic assays. During 30 years of research, the central 4-(3H)-pyrimidinone nucleus has been decorated with 2,6-dihaloaryl or cyclohexyl groups at the methylene at C6, alkyl- or (arylalkyl/aroylalkyl)thio/amino chains at C2, and hydrogen or a small alkyl group at C5. The further introduction of small (i.e., methoxy) groups at the C6 α-benzylic position furnished potency at the sub-nanomolar level against wild-type HIV-1 and at the nanomolar level against HIV-1 mutant strains. Importantly, some compounds of the DABO family exhibited preventative microbicidal activity, valuable in clinical settings where oral adherence rates are low.

Recent advances in triazole synthesis via click chemistry and their pharmacological applications: A review

Click chemistry is a flexible method featuring only the most feasible and efficient chemical reactions. The synthesis of 1,2,3-triazole from azides and terminal acetylenes using copper(I) as a catalyst is an extremely powerful reaction due to the extreme dependability, good selectivity, and biocompatibility of the starting materials. Triazole molecules are more than simple passive linkers; through hydrogen bonding and dipole interactions, they rapidly bind with biological targets. Its applications in drug development are expanding, ranging from target-oriented in situ chemistry and combinatorial mechanisms for lead generation to bioconjugation methods to study proteins and DNA. The click chemistry has frequently been used to speed up drug discovery and optimization processes in the past few years. The click chemistry reaction based on copper-catalyzed azide-alkyne cycloaddition (CuAAC) is a biochemical process with applications in medicinal chemistry and chemical biology. Thus, click reactions are an essential component of the toolkit for medicinal chemistry and help medicinal chemists overcome the barriers in chemical reactions, increase throughput, and improve the standards of compound libraries. The review highlights the recent advancements in the copper-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry approach for synthesizing biologically important triazole moieties with a greater emphasis on synthesis methodologies and pharmacological applications. Additionally, the triazole-based FDA-approved drugs are also discussed with their mode of action to highlight the importance of the click chemistry approach in synthesizing the bioactive triazole compounds.

Click chemistry-aided drug discovery: A retrospective and prospective outlook

Click chemistry has emerged as a valuable tool for rapid compound synthesis, presenting notable advantages and convenience in the exploration of potential drug candidates. In particular, in situ click chemistry capitalizes on enzymes as reaction templates, leveraging their favorable conformation to selectively link individual building blocks and generate novel hits. This review comprehensively outlines and introduces the extensive use of click chemistry in compound library construction, and hit and lead discovery, supported by specific research examples. Additionally, it discusses the limitations and precautions associated with the application of click chemistry in drug discovery. Our intention for this review is to contribute to the development of a modular synthetic approach for the rapid identification of drug candidates.

Discovery of novel 2,3,4,5-tetrahydrospiro[benzo[c]azepine-1,1'-cyclohexan]-5-ol derivatives as PARP-1 inhibitors

As an essential marker of cancer treatment, PARP-1 inhibitors could effectively kill tumor cells through a mechanism known as synthetic lethality and are used to treat a variety of cancers. In order to explore novel PARP-1 inhibitors, a series of 22 novel erythrina derivatives were reported and preliminarily explored their mechanism of action. The antitumor activities against four human cancer cell lines including A549, OVCAR-3, HCT-116, and MCF-7 were evaluated, and the preliminary SARs were summarized. Among them, compound 11b exhibited better anti-proliferative effects against A549 cells (IC50 = 1.95 µM). The SI results showed that compound 11b had low toxicity. Moreover, compound 11b displayed excellent PARP-1 inhibitory activities with IC50 values of 19.24 nM. In addition, molecular docking studies provided the rational binding modes of compound 11b in complexes with PARP-1. The flow cytometry assays revealed that compound 11b could induce apoptosis of A549 cells (P < 0.001). Simultaneously, compound 11b could effectively reduce the formation of PAR (P < 0.001). The ADMET prediction results indicated compound 11b had similar properties to rucaparib. Collectively, compound 11b has potential research value for further investigation.

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.

Recent applications of click chemistry in drug discovery

Introduction: Click chemistry has been exploited widely in the past to expedite lead discovery and optimization. Indeed, Copper-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry is a bioorthogonal reaction of widespread utility throughout medicinal chemistry and chemical biology. Areas covered: The authors review recent applications of CuAAC click chemistry to drug discovery based on the literature published since 2013. Furthermore, the authors provide the reader with their expert perspectives on the area including their outlook on future developments. Expert opinion: Click chemistry reactions are an important part of the medicinal chemistry toolbox and offer substantial advantages to medicinal chemists in terms of overcoming the limitations of useful chemical synthesis, increasing throughput, and improving the quality of compound libraries. To explore new chemical spaces for drug-like molecules containing a high degree of structural diversity, it may be useful to merge the diversity-oriented synthesis and 'privileged' substructure-based strategy with bioorthogonal reactions using sophisticated automation and flow systems to improve productivity. Large compound libraries obtained in this way should be of great value for the discovery of bioactive compounds and therapeutic agents.

Recent trends in click chemistry as a promising technology for virus-related research

Click chemistry involves reactions that were originally introduced and used in organic chemistry to generate substances by joining small units together with heteroatom linkages (C-X-C). Over the last few decades, click chemistry has been widely used in virus-related research. Using click chemistry, the virus particle as well as viral protein and nucleic acids can be labeled. Subsequently, the labeled virions or molecules can be tracked in real time. Here, we reviewed the recent applications of click reactions in virus-related research, including viral tracking, the design of antiviral agents, the diagnosis of viral infection, and virus-based delivery systems. This review provides an overview of the general principles and applications of click chemistry in virus-related research.

Discovery of novel pyrrolopyrimidine/pyrazolopyrimidine derivatives bearing 1,2,3-triazole moiety as c-Met kinase inhibitors

Six series of pyrrolo[2,3-d]pyrimidine and pyrazolo[3,4-d]pyrimidine derivatives bearing 1,2,3-triazole moiety were designed and synthesized, and some bio-evaluation was also carried out. As a result, four points can be summarized: Firstly, some of compounds exhibited excellent cytotoxicity activity and selectivity with the IC₅₀ values in single-digit μm level. In particular, the most promising compound 16d showed equal activity to lead compound foretinib against A549, HepG2, and MCF-7 cell lines, with the IC₅₀ values of 4.79 ± 0.82, 2.03 ± 0.39, and 2.90 ± 0.43 μm, respectively. Secondly, the SARs and docking studies indicated that the in vitro antitumor activity of pyrrolo[2,3-d]pyrimidine derivatives bearing 1,2,3-triazole moiety was superior to the pyrazolo[3,4-d]pyrimidine derivatives bearing 1,2,3-triazole moiety. Thirdly, three selected compounds (16d, 18d, and 20d) were further evaluated for inhibitory activity against the c-Met kinase, and the 16d could inhibit the c-Met kinase selectively by experiments of enzyme-based selectivity. What is more, 16d could induce apoptosis of HepG2 cells and inhibitor the cell cycle of HepG2 on G2/M phase by acridine orange staining and cell cycle experiments, respectively.

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

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 EC₅₀ 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, CC₅₀ = 40.15 μM), pyrrolidin-1-ylmethanone (3b8, EC_50(IIIB) = 0.020 μM, EC_50(E138K) = 0.014 μM, CC₅₀ = 58.09 μM) and morpholinomethanone (3b9, EC_50(IIIB) = 0.020 μM, EC_50(E138K) = 0.027 μM, CC₅₀ = 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.

Discovery of novel anti-HIV agents via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry-based approach

INTRODUCTION

In recent years, a variety of new synthetic methodologies and concepts have been proposed in the search for new pharmaceutical lead structures and optimization. Notably, the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry approach has drawn great attention and has become a powerful tool for the generation of privileged medicinal skeletons in the discovery of anti-HIV agents. This is due to the high degree of reliability, complete specificity (chemoselectivity and regioselectivity), mild conditions, and the biocompatibility of the reactants.

AREAS COVERED

Herein, the authors describe the progress thus far on the discovery of novel anti-HIV agents via the CuAAC click chemistry-based approach.

EXPERT OPINION

CuAAC click chemistry is a proven protocol for synthesizing triazole products which could serve as basic pharmacophores, act as replacements of traditional scaffold or substituent modification, be a linker of dual-target or dual-site inhibitors and more for the discovery of novel anti-HIV agents. What's more, it also provides convenience and feasibility for dynamic combinatorial chemistry and in situ screening. It is envisioned that click chemistry will draw more attention and make more contributions in anti-HIV drug discovery in the future.