Arylthiopyrrole (AThP) Derivatives as Non-Nucleoside HIV-1 Reverse Transcriptase Inhibitors: Synthesis, Structure–Activity Relationships, and Docking Studies (Part 1)

Quinolinonyl Derivatives as Dual Inhibitors of the HIV-1 Integrase Catalytic Site and Integrase-RNA interactions

The HIV-1 integrase (IN) plays a critical role in the viral lifecycle by integrating the viral DNA into the host chromosome. The catalytic function of IN has been exploited as a target, with five drugs acting as active site binders (IN strand transfer inhibitors, INSTIs). However, IN mutations conferring low-level resistance to INSTIs have been reported. Therefore, new IN inhibitors with different mechanisms of action are needed. The allosteric inhibition of IN, exerted by allosteric IN inhibitors (ALLINIs), is gaining interest. ALLINIs inhibit IN by inducing aberrant IN multimerization with different mechanisms. Furthermore, recent discoveries unveiled that IN has an under-studied yet equally vital second function. This involves IN binding to the RNA genome in virions, necessary for proper virion maturation. In this work, we describe a series of quinolinonyl derivatives as inhibitors of both the IN catalytic functions and IN-RNA interactions, which impair both early and late steps of viral replication.

Synthesis of Multi-Substituted Pyrrole Derivatives Through [3+2] Cycloaddition with Tosylmethyl Isocyanides (TosMICs) and Electron-Deficient Compounds

Pyrrole and its polysubstituted derivatives are important five-membered heterocyclic compounds, which exist alone or as a core framework in many pharmaceutical and natural product structures, some of which have good biological activities. The Van Leusen [3+2] cycloaddition reaction based on tosylmethyl isocyanides (TosMICs) and electron-deficient compounds as a substrate, which has been continuously developed due to its advantages such as operationally simple, easily available starting materials, and broadly range of substrates, is one of the most convenient methods to synthetize pyrrole heterocycles. In this review, we discuss the different types of two carbon synthons in the Van Leusen pyrrole reaction and give a summary of the progress of these synthesis methods in the past two decades.

Dual vicinal functionalisation of heterocycles via an interrupted Pummerer coupling/[3,3]-sigmatropic rearrangement cascade

A dual vicinal functionalisation cascade involving the union of heterocycles and allyl sulfoxides is described. In particular, the approach provides efficient one-step access to biologically relevant and synthetically important C3 thio, C2 carbo substituted indoles. The reaction operates under mild, metal free conditions and without directing groups, via an interrupted Pummerer coupling of activated allyl sulfoxides, generating allyl heteroaryl sulfonium salts that are predisposed to a charge accelerated [3,3]-sigmatropic rearrangement.

Microwave assisted aminocatalyzed [3 + 2] annulation between α-iminonitriles and succinaldehyde: synthesis of pyrrole-3-methanols and related polycyclic ring systems

A quick and highly efficient method for the synthesis of substituted pyrrole-3-methanols from α-iminonitriles and succinaldehyde under microwave irradiation is reported with good to high yields (up to 75%).

Pyrroloaryls and pyrroloheteroaryls: Inhibitors of the HIV fusion/attachment, reverse transcriptase and integrase

Heterocyclic compounds execute a very important role in drug design and discovery. This article provides the basic milestones of the research for pyrroloaryl and pyrroloheteroaryl based components targeting HIV viral replication cycle. Anti-HIV activity is elaborated for several classes of pyrrolo-compounds as pyrrolopyridines, pyrrolopyrimidines, pyrrolopyridazines, pyrrolobenzodiazepinones, pyrrolobenzothiazepines, pyrrolobenzoxazepinones, pyrrolophenanthridines, pyrroloquinoxalines, pyrrolotriazines, pyrroloquinolines, pyrrolopyrazinones, pyrrolothiatriazines, arylthiopyrroles and pyrrolopyrazolones targeting two essential HIV enzymes, reverse transcriptase and integrase as well as attachment/fusion of HIV virons to the host CD-4 cell. Such attempts were resulted in a discovery of highly potent anti-HIV agents suitable for clinical trials, for example, BMS-378806, BMS-585248, BMS-626529, BMS-663068, BMS-488043 and BMS-663749, etc. as anti-HIV attachment agents, triciribine, QX432, BI-1 and BI-2 as HIV RT inhibitors which are in preclinical or clinical development. Mechanism of action of compounds presented in this article towards the suppression of HIV attachment/fusion as well as against the activities of HIV enzymes reverse transcriptase and integrase has been discussed. Relationships of new compounds' molecular framework and HIV viral target has been overviewed in order to facilitate further construction of promising anti-HIV agents in future drug discovery process.

Deep eutectic solvent: a simple, environmentally benign reaction media for regioselective synthesis of 2,3,4-trisubstituted 1H-pyrroles

A greener, rapid and highly efficient synthetic protocol for the construction of pyrroles has been achieved.

Convenient one-pot multicomponent strategy for the synthesis of 6-pyrrolylpyrimidines

An easy method to construct diheteroaryls from α-aroylidineketene dithioacetals 2 in a multicomponent fashion. The reaction proceeds with high chemo/regioselectivity to give 4-alkoxy-6-(4-aryl-1H-pyrrol-3-yl)pyrimidin-2-amines in high yields by reacting 2 with p-tolylsulfonyl)methyl isocyanide 3 (TosMIC), guanidine nitrate 5 and alcohol in the presence of NaH/THF via cycloaddition.

HIV-1 NNRTIs: structural diversity, pharmacophore similarity, and implications for drug design

Nonnucleoside reverse transcriptase inhibitors (NNRTIs) nowadays represent very potent and most promising anti-AIDS agents that specifically target the HIV-1 reverse transcriptase (RT). However, the effectiveness of NNRTI drugs can be hampered by rapid emergence of drug-resistant viruses and severe side effects upon long-term use. Therefore, there is an urgent need to develop novel, highly potent NNRTIs with broad spectrum antiviral activity and improved pharmacokinetic properties, and more efficient strategies that facilitate and shorten the drug discovery process would be extremely beneficial. Fortunately, the structural diversity of NNRTIs provided a wide space for novel lead discovery, and the pharmacophore similarity of NNRTIs gave valuable hints for lead discovery and optimization. More importantly, with the continued efforts in the development of computational tools and increased crystallographic information on RT/NNRTI complexes, structure-based approaches using a combination of traditional medicinal chemistry, structural biology, and computational chemistry are being used increasingly in the design of NNRTIs. First, this review covers two decades of research and development for various NNRTI families based on their chemical scaffolds, and then describes the structural similarity of NNRTIs. We have attempted to assemble a comprehensive overview of the general approaches in NNRTI lead discovery and optimization reported in the literature during the last decade. The successful applications of medicinal chemistry strategies, crystallography, and computational tools for designing novel NNRTIs are highlighted. Future directions for research are also outlined.

Synthesis of novel derivatives of 4-amino-3-(2-furyl)-5-mercapto-1,2,4-triazole as potential HIV-1 NNRTIs

A series of 5-alkylthio (2a-d), 4-arylideneamino (3a-d) and 4-arylideneamino-5-alkylthio derivatives (4a-f) of 4-amino-3-(2-furyl)-5-mercapto-1,2,4-triazole (1) were synthesized by alkylation of the parent compound with alkyl halides and condensation with aldehydes, respectively. Sulfanyl dimers 5a-d and 4-iminomethyl dimer 6 were correspondingly prepared by reaction with alkane dibromides and 1,4-diformylbenzene. Mannich base 7 was also synthesized by aminomethylation of the 3-sulfanyltriazole 1 at the N1 position. The newly designed and synthesized substituted s-triazole derivatives were assayed for anti-HIV-1 activity by examination of their inhibition of HIV-1-induced cytopathogenicity in MT-4 cells and by determination of their inhibitory effect on HIV-1 reverse transcriptase. Compound 4e was found to be the most active inhibitor against HIV-1 replication in cell culture (EC50 = 12 microM) and against HIV-1 reverse transcriptase (IC50 = 43.5 microM), which provided a good lead for further optimization.

Arylthiopyrrole (AThP) Derivatives as Non-Nucleoside HIV-1 Reverse Transcriptase Inhibitors: Synthesis, Structure–Activity Relationships, and Docking Studies (Part 2)

Arylthio isopropyl pyridinylmethylpyrrolemethanols (AThPs) have been recently reported as a new class of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) inhibitors acting at the non-nucleoside binding site (NNBS) of this enzyme. Docking experiments of the potent inhibitors 4k (IC(50) = 0.24 microM, SI = 167) and 5e (IC(50) = 0.11 microM, SI > 1667) of wild-type RT prompted the synthesis and biological evaluation of novel AThP derivatives featuring a number of polar groups in position 3 of the pyrrole ring and larger and more hydrophobic alicyclic substituents in place of the isopropyl group at position 4. Among the compounds synthesized and tested in cell-based assays against HIV-1 infected cells, 19b was the most active, with EC(50) = 0.007 microM, CC(50) = 114.5 microm, and SI = 16357. This compound and its precursor 18b retained interesting activities against clinically relevant drug-resistant RT forms carrying K103N, Y181I, and L100I mutations. Docking calculations of 10, 14, 18b, and 19b were also performed to investigate their binding mode into the RT NNBS and to rationalize both structure-activity relationship and resistance data.