Structural modifications of CH(OH)-DAPYs as new HIV-1 non-nucleoside reverse transcriptase inhibitors

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.

Recent discoveries in HIV-1 reverse transcriptase inhibitors

HIV-1 reverse transcriptase inhibitors (RTIs) are indispensable components of highly active antiretroviral therapy (HAART), which has achieved great success in controlling AIDS epidemic in reducing drastically the morbidity and mortality of HIV-infected patients. RTIs are divided into two categories, nucleoside reverse transcriptase inhibitors (NRTIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs). In this review, the recent discoveries in NRTIs and NNRTIs, including approved anti-HIV drugs and noteworthy drug candidates in different development stages, are summarized, and their future direction is prospected.

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.

Synthesis and anti-human immunodeficiency virus activity of substituted ( o,o-difluorophenyl)-linked-pyrimidines as potent non-nucleoside reverse transcriptase inhibitors

With the worldwide number of human immunodeficiency virus positive patients stagnant and the increasing emergence of viral strains resistant to current treatment, the development of novel anti-human immunodeficiency virus drug candidates is a perpetual quest of medicinal chemists. Herein, we report a novel group of diarylpyrimidines, non-nucleoside reverse transcriptase inhibitors, which represents an important class of current anti-human immunodeficiency virus therapy. Series of diarylpyrimidines containing o,o-difluorophenyl (A-arm), 4-cyanophenylamino (B-arm), and a small substituent (e.g. NH₂, OMe) at positions 2, 4, and 6 of the pyrimidine ring were prepared. The A-arm was modified in the para position (F or OMe) and linked to the central pyrimidine core with a variable spacer (CO, O, NH). Antiviral activities of 20 compounds were measured against wild type human immunodeficiency virus-1 and mutant reverse transcriptase strains (K103N, Y181C) using a cytoprotection assay. To the most promising structural motives belong the o,o-difluoro-p-methoxy A-arm in position 4, and the amino group in position 6 of pyrimidine. Single digit nanomolar activities with no significant toxicity (CC₅₀ > 17,000 nM) were found for compounds 35 (EC₅₀ = 2 nM), 37 (EC₅₀ = 3 nM), and 13 (EC₅₀ = 4 nM) having O, NH, and CO linkers, respectively.

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.

Double Variational Binding--(SMILES) Conformational Analysis by Docking Mechanisms for Anti-HIV Pyrimidine Ligands

Variational quantitative binding–conformational analysis for a series of anti-HIV pyrimidine-based ligands is advanced at the individual molecular level. This was achieved by employing ligand-receptor docking algorithms for each molecule in the 1,3-disubstituted uracil derivative series that was studied. Such computational algorithms were employed for analyzing both genuine molecular cases and their simplified molecular input line entry system (SMILES) transformations, which were created via the controlled breaking of chemical bonds, so as to generate the longest SMILES molecular chain (LoSMoC) and Branching SMILES (BraS) conformations. The study identified the most active anti-HIV molecules, and analyzed their special and relevant bonding fragments (chemical alerts), and the recorded energetic and geometric docking results (i.e., binding and affinity energies, and the surface area and volume of bonding, respectively). Clear computational evidence was also produced concerning the ligand-receptor pocket binding efficacies of the LoSMoc and BraS conformation types, thus confirming their earlier presence (as suggested by variational quantitative structure-activity relationship, variational-QSAR) as active intermediates for the molecule-to-cell transduction process.