Synthesis, biological activity and docking study of imidazol-5-one as novel non-nucleoside HIV-1 reverse transcriptase inhibitors

Synthesis of 4-Hydroxy-5-phenylaminoimidazoles through a Three-Component Reaction of Sulfur Ylides, Nitrosobenzenes, and Amidines

A novel annulation reaction of amidines with sulfur ylides and nitrobenzenes has been developed, affording various novel 4-hydroxy-5-phenylaminoimidazoles in moderate to excellent yields. The 4-hydroxy-5-phenylaminoimidazoles have been further converted into α-ketoamide and imidazol-4-imine derivatives. Moreover, a plausible mechanism for this multicomponent reaction is proposed.

Two Disaccharide-Bearing Polyethers, K-41B and K-41Bm, Potently Inhibit HIV-1 via Mechanisms Different from That of Their Precursor Polyether, K-41A

The screening of novel antiviral agents from marine microorganisms is an important strategy for new drug development. Our previous study found that polyether K-41A and its analog K-41Am, derived from a marine Streptomyces strain, exhibit anti-HIV activity by suppressing the activities of HIV-1 reverse transcriptase (RT) and its integrase (IN). Among the K-41A derivatives, two disaccharide-bearing polyethers-K-41B and K-41Bm-were found to have potent anti-HIV-1IIIB activity in vitro. This study aimed to clarify whether K-41B and K-41Bm have inhibitory effects on different HIV-1 strains or whether these two derivatives have mechanisms of action different from that of their precursor, K-41A. An anti-HIV-1 assay indicated that K-41B and K-41Bm have potent anti-HIV-1BaL activity, with low 50% inhibitory concentrations (IC50s) (0.076 and 0.208 μM, respectively) and high selective indexes (SIs) (58.829 and 31.938, respectively) in the peripheral blood mononuclear cell (PBMC)-HIV-1BaL system. The time-of-addition (TOA) assay indicated that K-41B and K-41Bm may exert antiviral effects by activating multiple stages of HIV-1 replication. A cell protection assay indicated that the pretreatment of cells with K-41B or K-41Bm has almost no inhibitory effect on HIV-1 infection. A virus inactivation assay indicated that pretreatment of the virus with K-41B or K-41Bm inhibits HIV-1 infection by 60%. A cell-cell fusion assay showed that K-41B and K-41Bm blocked the cell fusion mediated by viral envelope proteins. The HIV-1 key enzyme experiment also indicated that both compounds have certain inhibitory effects on HIV-1 IN. Furthermore, molecular docking showed that K-41B and K-41Bm interact with several viral and host proteins, including HIV-1 IN, an envelope protein (gp120), a transmembrane protein (gp41), and cell surface receptors (CD4, CCR5, and CXCR4). Overall, in addition to having a similar anti-HIV-1 mechanism of inhibiting HIV-1 IN like the precursor polyether K-41A, the disaccharide-bearing polyether derivatives K-41B and K-41Bm may also inhibit viral entry. This suggests that they display anti-HIV-1 mechanisms that are different from those of their precursor polyethers.

1,2,4-Triazole-Tethered Indolinones as New Cancer-Fighting Small Molecules Targeting VEGFR-2: Synthesis, Biological Evaluations and Molecular Docking

Targeting the VEGFR-2 signaling pathway is an inveterate approach toward combating pancreatic and hepatocellular cancers. Based on Sunitinib, the FDA-approved VEGFR-2 inhibitor, novel indolin-2-one-triazole hybrids were designed and synthesized as anti-hepatocellular and anti-pancreatic cancer agents with VEGFR-2 inhibitory activity. All the targeted compounds were assessed for their anti-cancer activity, revealing IC50 values extending from 0.17 to 4.29 µM for PANC1 and 0.58 to 4.49 µM for HepG2 cell lines. An extensive SAR study was conducted to explore the effect of different substituents along with N-alkylation. The potent anti-cancer analogs 11d, 11e, 11g, 11k and 14c were evaluated for their VEGFR-2 inhibitory actions, where their IC50 values ranged from 16.3 to 119.6 nM compared to Sorafenib, which revealed an IC50 of 29.7 nM, having compound 11d as the most active analog. An in silico ADME study was performed to confirm the drug-likeness of the synthesized compounds. Finally, molecular docking simulation was conducted for the most potent VEGFR-2 inhibitor (11d), demonstrating the strong binding with the vital amino acid residues of the VEGFR-2 ATP binding site.

Characterization of the Photophysical Behavior of DFHBI Derivatives: Fluorogenic Molecules that Illuminate the Spinach RNA Aptamer

( Z)-5-(3,5-Difluoro-4-hydroxybenzylidene)-2,3-dimethyl-3,5-dihydro-4 H-imidazol-4-one (DFHBI) and its analogues are fluorogenic molecules that bind the Spinach aptamer (a small RNA molecule), which was selected for imaging RNA. They are extremely weakly fluorescent in liquid solvents. It had been hypothesized that photoisomerization is a very efficient nonradiative process of deactivation. We show, consistent with the results of other studies, that if the isomerization is impeded, the fluorescence signal is enhanced significantly. In addition, we provide a thorough characterization of the photophysical behavior of DFHBI and its derivatives, notably that of ( Z)-5-(3,5-difluoro-4-hydroxybenzylidene)-2-methyl-3-((perfluorophenyl)methyl)-3,5-dihydro-4 H-imidazol-4-one (PFP-DFHBI) in various solvent environments. Solvent-dependent studies were performed with various mixtures of solvents. The results suggest that hydrogen bonding or strong interactions of the solvents with the phenolic-OH group change the absorption band near 420-460 nm and the nature of emission near 430 and 500 nm through various degrees of stabilization and the transformation between the neutral and the anionic species at both ground and excited states. These observations are confirmed by using a methoxy-substituted molecule (( Z)-5-(4-methoxybenzylidene)-2,3-dimethyl-3,5-dihydro-4 H-imidazol-4-one), where the 420-460 nm band is absent in the presence of methanol and the spectra are similar to those of PFP-DFHBI in noninteracting solvents, such as acetonitrile and dichloromethane. Thus, in addition to the major role of photoisomerization as a nonradiative process of deactivation of the excited state, the fluorescence of DFHBI-type molecules is very sensitively dependent upon the pH of the medium as well as upon solvent-specific interactions, such as hydrogen-bonding ability and polarity.

Synthesis, characterization, antioxidant power and acute toxicity of some new azo-benzamide and azo-imidazolone derivatives with in vivo and in vitro antimicrobial evaluation

In this research paper, a stepwise chemical reaction was conducted to synthesize and develop of a new potent azo-oxazolone, which was used as prototypical molecule for production of two series of azo-benzimide (5a-j) and azo-imidazolone (6a-j). FT-IR, ¹H NMR, ¹³C NMR and CHN analysis were used for the structural elucidation. The high biological efficiency of newly obtained compounds was confirmed by in vitro antioxidant efficacy and in vitro antimicrobial activity against gram-positive and gram-negative bacteria via disc diffusion and tube dilution techniques. In addition, in vivo anti-microbial activity of some of the synthesized compounds was determined by using burnt rats which infected by Staphylococcus aureus. Tested compounds have shown high anti-microbial activity and wound healing in comparison to ucederm as a control. In vivo acute toxicity was carried out by up and down method for the compounds 4, 5d and 6d. The limited test dose was 2000 mg/kg, while the maximum tolerated dose was 5000 mg/kg which has administered no lethality recorded.

Dihydropyrimidinone-isatin hybrids as novel non-nucleoside HIV-1 reverse transcriptase inhibitors

A novel series of substituted N-(2-(2,3-dioxoindolin-1-yl)acetyl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide was designed, synthesized and evaluated for in vitro Reverse Transcriptase (RT) inhibitory activity. This series is a combination of peculiar structural features from leading scaffolds of [(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT) and oxyindole. In vitro screening led to identification of two hybrids (9c and 9d) possessing higher RT inhibitory activity than the standard rilpivirine. Docking study was performed to study the binding orientations of synthesized hybrids towards RT enzyme.

Synthesis of new simplified hemiasterlin derivatives with α,β-unsaturated carbonyl moiety

In this Letter, we report a convenient and efficient method for the synthesis of new simplified derivatives of hemiasterlin in which the α,α-dimethylbenzylic moiety A is replaced by α,β-unsaturated aryl groups as Michael acceptor. Most of these derivatives have a strong cytotoxic activity on three human tumor cell lines (KB, Hep-G2 and MCF7). Analogs 17b and 17f showed a high cytotoxicity against KB and Hep-G2 cancer cell lines comparable to paclitaxel and ellipticine.

Anti-HIV drug development through computational methods

Although highly active antiretroviral therapy (HAART) is effective in controlling the progression of AIDS, the emergence of drug-resistant strains increases the difficulty of successful treatment of patients with HIV infection. Increasing numbers of patients are facing the dilemma that comes with the running out of drug combinations for HAART. Computational methods play a key role in anti-HIV drug development. A substantial number of studies have been performed in anti-HIV drug development using various computational methods, such as virtual screening, QSAR, molecular docking, and homology modeling, etc. In this review, we summarize recent advances in the application of computational methods to anti-HIV drug development for five key targets as follows: reverse transcriptase, protease, integrase, CCR5, and CXCR4. We hope that this review will stimulate researchers from multiple disciplines to consider computational methods in the anti-HIV drug development process.

The nucleoside reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, and protease inhibitors in the treatment of HIV infections (AIDS)

The majority of the drugs currently used for the treatment of HIV infections (AIDS) belong to either of the following three classes: nucleoside reverse transcriptase inhibitors (NRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs), and protease inhibitors (PIs). At present, there are 7 NRTIs, 5 NNRTIs, and 10 PIs approved for clinical use. They are discussed from the following viewpoints: (i) chemical formulae; (ii) mechanism of action; (iii) drug combinations; (iv) clinical aspects; (v) preexposure prophylaxis; (vi) prevention of mother-to-child transmission; (vii) their use in children; (viii) toxicity; (ix) adherence (compliance); (x) resistance; (xi) new NRTIs, NNRTIs, or PIs in (pre)clinical development; and (xii) the prospects for a "cure" of the disease.