Synthesis and biological evaluation of pyrimidine nucleosides fused with 3',4'-tetrahydrofuran ring

Pyrimidine nucleosides fused with 3',4'-tetrahydrofuran ring were synthesized, starting from 1,2;5,6-di-O-isopropylidene-D-glucose and assayed for antiviral activities. Thymine analogue 1 and its corresponding 2'-deoxy analogue 3 exhibited high cytotoxicity instead of giving antiviral activities.     

Synthesis of 6-arylvinyl analogues of the HIV drugs SJ-3366 and Emivirine

This paper reports the synthesis and the antiviral activities of a series of 6-arylvinyl substituted analogues of SJ-3366, a highly potent agent against HIV. The objective was to investigate whether substitution of the 6-arylketone with a 6-arylvinyl group could lead to an improved antiviral activity against HIV-1. The most active compounds 1-ethoxymethyl, 1-(2-propynyloxymethyl), and 1-(2-methyl-3-phenylallyloxymethyl) substituted 6-[1-(3,5-dimethylphenyl)vinyl]-5-ethyl-1H-pyrimidine-2,4-dione (5b, 16, and 18) showed activities against HIV-1 wild type in the range of Efavirenz, and moderate activities against Y181C and Y181C+K103N mutant strains were also observed.     

Synthesis and Biological Evaluation of Pyrimidine Nucleosides Fused with 3′,4′-Tetrahydrofuran Ring

Abstract

Pyrimidine nucleosides fused with 3′,4′-tetrahydrofuran ring were synthesized, starting from 1,2;5,6-di-O-isopropylidene-D-glucose and assayed for antiviral activities. Thymine analogue 1 and its corresponding 2′-deoxy analogue 3 exhibited high cytotoxicity instead of giving antiviral activities.     

Simple synthesis of novel acyclic (e)-bromovinyl nucleosides as potential antiviral agents

In these study, novel acyclic (E)-bromovinyl nucleosides were synthesized as potential antiviral agents. The coupling of the allylic bromide 9 with bases (thymine, uracil, 5-fluorouracil, 5-iodouracil, cytosine, adenine) afforded a series of novel acyclic nucleosides. The synthesized compounds were evaluated for their antiviral activity against various viruses such as HIV-1, HSV-1, HSV-2, and HCMV. 5-Iodouracil analogue 19 showed weak anti-HIV-1 activity.     

Identification of HIV-1 integrase inhibitors via three-dimensional database searching using ASV and HIV-1 integrases as targets

Integration of viral DNA into the host cell genome is a critical step in the life cycle of HIV. This essential reaction is catalyzed by integrase (IN) through two steps, 3'-processing and DNA strand transfer. Integrase is an attractive target for drug design because there is no known cellular analogue and integration is essential for successful replication of HIV. A computational three-dimensional (3-D) database search was used to identify novel HIV-1 integrase inhibitors. Starting from the previously identified Y3 (4-acetylamino-5-hydroxynaphthalene-2,7-disulfonic acid) binding site on the avian sarcoma virus integrase (ASV IN), a preliminary search of all compounds in the nonproprietary, open part of the National Cancer Institute 3-D database yielded a collection of 3100 compounds. A more rigorous scoring method was used to rescreen the 3100 compounds against both ASV IN and HIV-1 IN. Twenty-two of those compounds were selected for inhibition assays against HIV-1 IN. Thirteen of the 22 showed inhibitory activity against HIV-1 IN at concentrations less than 200 microM and three of them showed antiviral activities in HIV-1 infected CEM cells with effective concentrations (EC50) ranging from 0.8 to 200 microM. Analysis of the computer-generated binding modes of the active compounds to HIV-1 IN showed that simultaneous interaction with the Y3 site and the catalytic site is possible. In addition, interactions between the active compounds and the flexible loop involved in the binding of DNA by IN are indicated to occur. The structural details and the unique binding motif between the HIV-1 IN and its inhibitors identified in the present work may contribute to the future development of IN inhibitors.     

SPL7013 Gel (VivaGel®) retains potent HIV-1 and HSV-2 inhibitory activity following vaginal administration in humans

SPL7013 Gel (VivaGel(?)) is a microbicide in development for prevention of HIV and HSV. This clinical study assessed retention and duration of antiviral activity following vaginal administration of 3% SPL7013 Gel in healthy women. Participants received 5 single doses of product with ≥5 days between doses. A cervicovaginal fluid (CVF) sample was collected using a SoftCup? pre-dose, and immediately, or 1, 3, 12 or 24 h post-dose. HIV-1 and HSV-2 antiviral activities of CVF samples were determined in cell culture assays. Antiviral activity in the presence of seminal plasma was also tested. Mass and concentration of SPL7013 in CVF samples was determined. Safety was assessed by reporting of adverse events. Statistical analysis was performed using the Wilcoxon signed-rank test with Bonferroni adjustment; p≤0.003 was significant. Eleven participants completed the study. Inhibition of HIV-1 and HSV-2 by pre-dose CVF samples was negligible. CVF samples obtained immediately after dosing almost completely inhibited (median, interquartile range) HIV-1 [96% (95,97)] and HSV-2 [86% (85,94)], and activity was maintained in all women at 3 h (HIV-1 [96% (95,98), p?=?0.9]; HSV-2 [94% (91,97), p?=?0.005]). At 24 h, >90% of initial HIV-1 and HSV-2 inhibition was maintained in 6/11 women. SPL7013 was recovered in CVF samples obtained at baseline (46% of 105 mg dose). At 3 and 24 h, 22 mg and 4 mg SPL7013, respectively, were recovered. More than 70% inhibition of HIV-1 and HSV-2 was observed if there was >0.5 mg SPL7013 in CVF samples. High levels of antiviral activity were retained in the presence of seminal plasma. VivaGel was well tolerated with no signs or symptoms of vaginal, vulvar or cervical irritation reported. Potent antiviral activity was observed against HIV-1 and HSV-2 immediately following vaginal administration of VivaGel, with activity maintained for at least 3 h post-dose. The data provide evidence of antiviral activity in a clinical setting, and suggest VivaGel could be administered up to 3 h before coitus. TRIAL REGISTRATION: The study is registered at ClinicalTrials.gov under identifier: NCT00740584.     

Synthesis and antiviral activity of new dimeric inhibitors against HIV-1

This paper describes the synthesis and the antiviral activities of dimeric compounds derived from homo and asymmetric combinations of N-1 propynyloxymethyl analogues 1a,b of MKC-442, an N-1 4-iodobenzyloxymethyl analogue of TNK-651 5, potent contraceptive norgestrel and AZT. They were obtained by Sonogashira reaction, 'click' chemistry or Pd-catalyzed oxidative coupling. The iodo precursor 5 turned out as a potent compound against wild type and mutated HIV-1 virus. All dimeric compounds showed lower activity against HIV-1 than MKC-442, except the asymmetric dimer of AZT and 1a which showed an activity comparable to MKC-442.     

Design and Synthesis of Novel 1′,3′-Dioxolane 5′-Deoxyphosphonic Acid Purine Analogues as Potent Antiviral Agents

Electronic parameters of 1′,3 ′-oxygen play significant roles in steering the conformation of nucleoside phosphonic acid analogues. To investigate the relationship of two oxygen atoms with antiviral enhancement, novel 1′,3 ′-dioxolane 5 ′-deoxyphosphonic acid purine analogues were synthesized via de novo acyclic stereoselective route from acrolein and glycolic acid. The synthesized nucleoside phosphonic acid analogues 14 and 19 were subjected to antiviral screening against several viruses, such as HIV-1, HSV-1, HSV-2, and HCMV. The guanine analogue 19 exhibits in vitro anti-HIV-1 activity similar to that of 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA) in MT-4 cells.     

Highly stereoselective synthesis and biological properties of nucleoside analogues bearing a spiro inserted oxirane ring

Starting from 2',5'-di-O-TBDMS-3'-ketouridine 1 or its thymine analogue 2, both xylo (3-10) and ribo (20) epimers of a series of 3"-substituted 3'-spironucleosides have been obtained in good yields and with a total stereoselectivity. Most new compounds were moderately cytotoxic with in some cases slightly selective antiproliferative activities. None of these compounds was active against HIV, but some other antiviral activities against HSV-2, CMV, EBV, or VZV, in the micromolar range, were noted in specific cases.     

Homogeneous high-throughput screening assays for HIV-1 integrase 3beta-processing and strand transfer activities

HIV-1 integrase (HIV-IN) is a well-validated antiviral drug target catalyzing a multistep reaction to incorporate the HIV-1 provirus into the genome of the host cell. Small molecule inhibitors of HIV-1 integrase that specifically target the strand transfer step have demonstrated efficacy in the suppression of virus propagation. However, only few specific strand transfer inhibitors have been identified to date, and the need to screen for novel compound scaffolds persists. Here, the authors describe 2 homogeneous time-resolved fluorescent resonance energy transfer-based assays for the measurement of HIV-1 integrase 3'-processing and strand transfer activities. Both assays were optimized for high-throughput screening formats, and a diverse library containing more than 1 million compounds was screened in 1536-well plates for HIV-IN strand transfer inhibitors. As a result, compounds were found that selectively affect the enzymatic strand transfer reaction over 3beta processing. Moreover, several bioactive molecules were identified that inhibited HIV-1 reporter virus infection in cellular model systems. In conclusion, the assays presented herein have proven their utility for the identification of mechanistically interesting and biologically active inhibitors of HIV-1 integrase that hold potential for further development into potent antiviral drugs.     

Synthesis and hiv-1 integrase inhibitory activities of catechol and bis-Catechol derivatives

Fourteen catechol and bis-catechol derivatives have been synthesised and tested for their HIV-1 inhibitory activities. The six more active molecules have been tested for their antiviral activity and cytotoxicity. We have found that bis-catechols 1 and 2 are the most active HIV-1 integrase inhibitor whereas the best antiviral compound is 4.     

Polyfluoroaromatic stavudine (d4T) ProTides exhibit enhanced anti-HIV activity

Human Immunodeficiency Virus (HIV) damages the immune system and leads to the life-threatening acquired immunodeficiency syndrome (AIDS). Despite the advances in the field of antiretroviral treatment, HIV remains a major public health challenge.Nucleosides represent a prominent chemotherapeutic class for treating viruses, however their cellular uptake, kinase-mediated activation and catabolism are limiting factors. Herein, we report the synthesis and in vitro evaluation of stavudine (d4T) ProTides containing polyfluorinated aryl groups against two strains; HIV-1 (IIIB) and HIV-2 (ROD). ProTide 5d containing a meta-substituted pentafluorosulfanyl (3-SF₅) aryl group showed superior antiviral activity over the parent d4T and the nonfluorinated analogue 5a. ProTide 5d has low nanomolar antiviral activity; (IC₅₀ = 30 nM, HIV-1) and (IC₅₀ = 36 nM, HIV-2) which is over tenfold more potent than d4T. Interestingly, ProTide 5d showed a significantly high selectivity indices with SI = 1753 (HIV-1) and 1461 (HIV-2) which is more than twice that of the d4T. All ProTides were screened in wild type as well as thymidine kinase deficient (TK^?) cells. Enzymatic activation of ProTide 5d using carboxypeptidase Y enzyme and monitored using both ³¹P and ¹⁹F NMR is presented.     

APOBEC3A is a specific inhibitor of the early phases of HIV-1 infection in myeloid cells

Myeloid cells play numerous roles in HIV-1 pathogenesis serving as a vehicle for viral spread and as a viral reservoir. Yet, cells of this lineage generally resist HIV-1 infection when compared to cells of other lineages, a phenomenon particularly acute during the early phases of infection. Here, we explore the role of APOBEC3A on these steps. APOBEC3A is a member of the APOBEC3 family that is highly expressed in myeloid cells, but so far lacks a known antiviral effect against retroviruses. Using ectopic expression of APOBEC3A in established cell lines and specific silencing in primary macrophages and dendritic cells, we demonstrate that the pool of APOBEC3A in target cells inhibits the early phases of HIV-1 infection and the spread of replication-competent R5-tropic HIV-1, specifically in cells of myeloid origins. In these cells, APOBEC3A affects the amount of vDNA synthesized over the course of infection. The susceptibility to the antiviral effect of APOBEC3A is conserved among primate lentiviruses, although the viral protein Vpx coded by members of the SIV(SM)/HIV-2 lineage provides partial protection from APOBEC3A during infection. Our results indicate that APOBEC3A is a previously unrecognized antiviral factor that targets primate lentiviruses specifically in myeloid cells and that acts during the early phases of infection directly in target cells. The findings presented here open up new venues on the role of APOBEC3A during HIV infection and pathogenesis, on the role of the cellular context in the regulation of the antiviral activities of members of the APOBEC3 family and more generally on the natural functions of APOBEC3A.     

Synthesis and biological evaluation of novel 6-substituted 5-alkyl-2-(arylcarbonylmethylthio)pyrimidin-4(3H)-ones as potent non-nucleoside HIV-1 reverse transcriptase inhibitors

A novel series of 2-arylcarbonylmethylthio-6-arylmethylpyrimidin-4(3H)-ones have been synthesized and evaluated for in vitro anti-HIV activities in MT-4 cells. Most of these new compounds showed moderate to potent activities against wild-type HIV-1 with an EC(50) range from 8.97 microM to 0.010 microM. Among them, the 6-(3,5-dimethylbenzyl) analogue 5p was identified as the most promising compound (EC(50)=0.010 microM, SI>31,800) associated with moderate activity against the HIV-1 double mutant RT strain K103N+Y181C. The structure-activity relationships of these new congeners were further discussed.     

Effects of Cellular Activation on Anti-HIV-1 Restriction Factor Expression Profile in Primary Cells

Expression of cell-intrinsic antiviral factors suppresses HIV-1 replication. We hypothesized that cellular activation modulates host restriction and susceptibility to HIV-1 infection. We measured the gene expression of 34 antiviral factors in healthy peripheral blood mononuclear cells (PBMC). Cellular activation induced expression of interferon-stimulated gene 15 (ISG15), tripartite motif 5α (TRIM5α), bone marrow stromal cell antigen 2 (BST-2)/tetherin, and certain apolipoprotein B mRNA editing enzyme 3 (APOBEC3) family members. Expression of RTF1, RNA polymerase II-associated factor 1 (PAF1), TRIM11, TRIM26, and BST-2/tetherin correlated with decreased HIV-1 infectivity. This report demonstrates synchronous effects of activation-induced antiviral genes on HIV-1 infectivity, providing candidates for pharmacological manipulation.     

Design and synthesis of HIV-1 protease inhibitors. Novel tetrahydrofuran P2/P2'-groups interacting with Asp29/30 of the HIV-1 protease. Determination of binding from X-ray crystal structure of inhibitor protease complex

A series of HIV-1 protease inhibitors having new tetrahydrofuran P2/P2' groups have been synthesised and tested for protease inhibition and antiviral activity. Six novel 4-aminotetrahydrofuran derivatives were prepared starting from commercially available isopropylidene-alpha-D-xylofuranose yielding six symmetrical and six unsymmetrical inhibitors. Promising sub nanomolar HIV-1 protease inhibitory activities were obtained. The X-ray crystal structure of the most potent inhibitor (23, K(i) 0.25 nM) co-crystallised with HIV-1 protease is discussed and the binding compared with inhibitors 1a and 1b.     

Synthesis and Antiviral Activities of Enantiomeric 1-[2-(Hydroxymethyl) Cyclopropyl] Methyl Nucleosides

Abstract

Cyclopropyl carbocyclic nucleosides have been synthesized from the key intermediate 2 which was converted to the mesylated cyclopropyl methyl alcohol 3. Condensation of compound 3 with various purine and pyrimidine bases gave the desired nucleosides. All synthesized nucleosides were evaluated for antiviral activity and cellular toxicity. Among them adenine 22 and guanine 23 derivatives showed moderate antiviral activity against HIV-1 and HBV. None of the other compounds showed any significant antiviral activities against HIV-1, HBV, HSV-1 and HSV-2 in vitro up to 100μM.