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• (Re)emerging RNA viruses are responsible for highly fatal viral diseases. • Ribonucleoside analogs for clinical use in the treatment of RNA viruses. • Targeting viral RNA-dependent RNA polymerase. • Structure-activity relationship for RdRp inhibitory nucleosides. • Challenges in the design of new nucleosides. With several US Food and Drug Administration (FDA)-approved drugs and high barriers to resistance, nucleoside and nucleotide analogs remain the cornerstone of antiviral therapies for not only herpesviruses, but also HIV and hepatitis viruses (B and C); however, with the exception of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), for which vaccines have been developed at unprecedented speed, there are no vaccines or small antivirals yet available for (re)emerging viruses, which are primarily RNA viruses. Thus, herein, we present an overview of ribonucleoside analogs recently developed and acting as inhibitors of the viral RNA-dependent RNA polymerase (RdRp). They are new lead structures that will be exploited for the discovery of new antiviral nucleosides. [ABSTRACT FROM AUTHOR]

A molecularly imprinted polymer of Tenofovir (1), an FDA-approved acyclic nucleoside phosphonate with antiviral activity, was synthesized using a non-covalent approach. A pre-polymerization complex was formed between (1) and DMAEMA and in-house synthetic N1-[(2-methacryloyloxy)ethyl] thymine, with EGDMA as a cross-linker in an MeCN/H2O (9:1, 1:1) mixture as a porogen, giving an imprinting factor (IF) of 5.5 at 2.10−5 mol/L. Binding parameters were determined by the Freundlich–Langmuir model, Qmax and Ka, and well as the particle morphology for MIP and NIP. Finally, the release profiles, for MIP and NIP, were obtained at 25 °C and 37 °C, which is body temperature, in a phosphate buffer saline, pH 7.4, mimicking the blood pH value, to determine the potential sustained release of our polymeric materials. [ABSTRACT FROM AUTHOR]

The emergence of Multidrug Resistance (MDR) strains of bacteria has accelerated the search for new antibacterials. The specific bacterial peptidoglycan biosynthetic pathway represents opportunities for the development of novel antibacterial agents. Among the enzymes involved, Mur ligases, described herein, and especially the amide ligases MurC-F are key targets for the discovery of multi-inhibitors, as they share common active sites and structural features. [ABSTRACT FROM AUTHOR]

The enantiomeric synthesis of l-cyclopentenyl nucleosides is described. The key intermediate (+)-cyclopentenyl alcohol (8) was prepared from methyl-α-d-galactopyranoside 1 using a ring closing metathesis reaction. Transformation of the allylic alcohol 8 into the allylic acetate (9) or carbonate (10), allows their coupling with purine and pyrimidine bases under Pd(0)-catalyzed Tsuji–Trost allylic alkylation''s to yield 12a–c. The Pd catalyzed reaction was found to require the use of AlEt3. [Copyright &y& Elsevier]

Describes the biological activity of nucleosides and their phosphorylated derivatives. Role nucleic acids in the cells; Emphasis on the structural features of nucleosides; Scope for the variation in the sugar moiety.

Demonstrates the chiral synthesis of carbocyclic analogues of L-ribofuranosides. X-ray structure and confirmation of L-cyclopentyl carbocyclic ribonucleosides; Synthesis of racemic aristeromycin and its analogue; Direct coupling of a functionalized carbocyclic moiety with the corresponding heterocycles; Synthesis of the inosine derivative.

Derivatives of 6,9-dihydro- and 6,7,8,9-tetrahydro-2-thia-3,5,6,7,9-pentaazabenz[cd]azulenes representing a new heterocyclic system have been prepared by the cyclocondensation reaction of ethyl 5-amino-4-(1-methylhydrazino)-2-methylthiothieno[2,3-d]-pyrimidine-6-carboxylate with ethyl orthoformate and various aldehydes. [Copyright &y& Elsevier]

Nucleoside analogues are at the forefront of antiviral therapy for last decades. To circumvent some of their limitations, based on their metabolism, and in order to improve their anti‐viral potency and selectivity, several families of nucleoside analogues have been described through structural modifications at the sugar and heterocycles. The replacement of the oxygen of the nucleoside by a methylene has led to the family of carbocyclic (or cyclopentane) nucleoside analogues. Various potent anti‐HIV and anti‐HBV drugs belong to this family. Main syntheses of carbocyclic analogues of nucleosides used Diels‐Alder reactions (in racemic or asymmetric series), but also started from carbohydrates (ribose, glucose), as a source of optically active compounds, which then had to be transformed into carbacycles under various conditions. The growing interest in carbocyclic nucleosides has led several groups, including ours, to develop new analogues and to explore novel routes. This article will review some of the recent chemistry developed on selected five‐membered ring carbocyclic nucleosides. [ABSTRACT FROM AUTHOR]

The convenient preparation of three imidazo[1,2‐a]pyridine‐2‐carboxamide intermediates is reported through known Strecker–Ugi type multicomponent reactions, Tschitschibabin type condensations, and further synthetic sequences. The derivatives were then efficiently converted to novel 4‐chloro‐2‐(trifluoromethyl)pyrido[1,2‐e]purines by their original reactions with 2,2,2‐trifluoroacetamide, followed by subsequent dehydroxychlorination reactions. These compounds were cross‐coupled under microwave irradiation through SuzukiMiyaura and Sonogashira palladium(0) catalysis to various aromatic and alkynyl reagents, thus providing the related C‐4 substituted pyrido[1,2‐e]purines of biological interest in good yields. [ABSTRACT FROM AUTHOR]

The synthesis of a broad range of drugs bearing a (E)-but-2-enyl aliphatic side chain is described including an olefin acyclic olefin cross metathesis as key step. [ABSTRACT FROM AUTHOR]

[Display omitted] Emerging and reemerging viruses pose significant public health threats, underscoring the urgent need for new antiviral drugs. Recently, a novel family of antiviral acyclic nucleoside phosphonates (ANP) composed of a 4-(2,4-diaminopyrimidin-6-yl)oxy-but-2-enyl phosphonic acid skeleton (O -DAPy nucleobase) has shown promise. Among these, LAVR-289 stands out for its potent inhibitory effects against various DNA viruses. Despite its efficacy, LAVR-289s poor water solubility hampers effective drug delivery. To address this, innovative delivery systems utilizing lipidic derivatives have been explored for various administration routes. Submicron lyotropic liquid crystals (LLCs) are particularly promising drug carriers for the encapsulation, protection, and delivery of lipophilic drugs like LAVR-289. This study focuses on developing submicron-sized lipid mesophase dispersions, including emulsified L 2 phase, cubosomes, and hexosomes, by adjusting lipidic compounds such as Dimodan® U/J, Lecithins E80, and Miglyol® 812 N. These formulations aim to enhance the solubility and bioavailability of LAVR-289. In vitro evaluations demonstrated that LAVR-289-loaded LLCs at a concentration of 1 µM efficiently inhibited vaccinia virus in infected human cells, with no observed cytotoxicity. Notably, hexosomes exhibited the most favorable antiviral outcomes, suggesting that the internal mesophase structure plays a critical role in optimizing the therapeutic efficacy of this drug class. [ABSTRACT FROM AUTHOR]

In 2002, a new class of thymidylate synthase (TS) involved in the de novo synthesis of dTMP named Flavin-Dependent Thymidylate Synthase (FDTS) encoded by the thyX gene was discovered; FDTS is present only in 30% of prokaryote pathogens and not in human pathogens, which makes it an attractive target for the development of new antibacterial agents, especially against multi-resistant pathogens. We report herein the synthesis and structure-activity relationship of a novel series of hitherto unknown pyrido[1,2-e]purine-2,4(1H,3H)-dione analogues. Several synthetics efforts were done to optimize regioselective N1-alkylation through organopalladium cross-coupling. Modelling of potential hits were performed to generate a model of interaction into the active pocket of FDTS to understand and guide further synthetic modification. All those compounds were evaluated on an in-house in vitro NADPH oxidase assays screening as well as against Mycobacterium tuberculosis ThyX. The highest inhibition was obtained for compound 23a with 84.3% at 200 µM without significant cytotoxicity (CC50 > 100 μM) on PBM cells. [ABSTRACT FROM AUTHOR]

Following our previous results on an environmentally benign one-pot Sonogashira-cyclization protocol to obtain substituted furopyrimidine nucleosides under aqueous conditions, we investigate herein the Suzuki-Miyaura cross-coupling reactions of aryl and heteroaryl derivatives at the C5 position of unprotected 2'-deoxyuridine in the same media with a common catalyst system avoiding exotic ligands, since palladium acetate and triphenylphosphine afforded the expected products in moderate to good yields. [ABSTRACT FROM AUTHOR]

Abstract: An environmentally benign one-pot protocol was herein reported to obtain different substituted furopyrimidine nucleosides in aqueous conditions with a low catalysts loading. [Copyright &y& Elsevier]

The article presents a study which reviews previous literatures to describe the strategies used in making cyclonucleosides. It notes that the discovery of natural nucleosides from marine sponges was vital for the development of antileukemic Ara-C and antiviral agents Ara-A. It mentions that nucleosides application in chemotherapy and the recognition of stereo- or regioselective organic reactions can be made possible for the development of synthetic nucleosides with antiviral properties.

Unlike most DNA viruses, poxviruses replicate in the cytoplasm of host cells. They encode enzymes needed for genome replication and transcription, including their own thymidine and thymidylate kinases. Some herpes viruses encode only 1 enzyme catalyzing both reactions, a peculiarity used for prodrug activation to obtain maximum specificity. We have solved the crystal structures of vaccinia virus thymidylate kinase bound to TDP or brivudin monophosphate. Although the viral and human enzymes have similar sequences (42% identity), they differ in their homodimeric association and active-site geometry. The vaccinia TMP kinase dimer arrangement is orthogonal and not antiparallel as in human enzyme. This different monomer orientation is related to the presence of a canal connecting the edge of the dimer interface to the TMP base binding pocket. Consequently, the pox enzyme accommodates nucleotides with bulkier bases, like brivudin monophosphate and dGMP; these are efficiently phosphorylated and stabilize the enzyme. The brivudin monophosphate-bound structure explains the structural basis for this specificity, opening the way to the rational development of specific antipox agents that may also be suitable for poxvirus TMP kinase gene-based chemotherapy of cancer. [ABSTRACT FROM AUTHOR]

Abstract: The racemic synthesis of hitherto unknown 5-substituted-[1,2,3]-triazolo-3′-deoxycarbanucleosides and [1,2,3]-triazolo-[4,5-c]pyridin-4-one analogues is described. The key iodinated intermediate 10 was prepared in 10 steps using a malonic synthesis. Various alkynes were introduced at the C-5 position of 10 under optimized Pd(0)-catalyzed Sonogashira cross-coupling alkynylation to yield after deprotection 12a–i . The synthesis of their 8-aza-3-deazapurine analogues ( 13a–h ) was also accomplished through the heteroannulation of internal alkynes under aqueous dimethylamine. [Copyright &y& Elsevier]

Synthesis of [13C5]-labeled anti-HIV nucleosides, e.g. d4T, ddI, ddA, is described. The methodology used has been optimized due to the very high cost of the starting compound. The key step of this approach was the stereoselective dehomologation of 1,2:5,6-di-O-isopropylidene-3-oxo-α-d-glucofuranose (2) with periodic acid and sodium borohydride, which gave optically pure ribose derivative as the exclusive product. Nucleoside derivatives 6a–c were obtained from ribosylation of 5 with persilylated nucleobases under Vorbru¨ggen conditions. Deoxygenation of 9a–c under Corey-Winter conditions afforded the desired labeled nucleoside analogues 12a–c. [Copyright &y& Elsevier]

New acyclic pyrimidine nucleoside phosphonate prodrugs with a 4-(2,4-diaminopyrimidin-6-yl)oxy-but-2-enyl]phosphonic acid skeleton (O -DAPy nucleobase) were prepared through a convergent synthesis by olefin cross-metathesis as the key step. Several acyclic nucleoside 4-(2,4-diaminopyrimidin-6-yl)oxy-but-2-enyl]phosphonic acid prodrug exhibited in vitro antiviral activity in submicromolar or nanomolar range against varicella zoster virus (VZV), human cytomegalovirus (HCMV), human herpes virus type 1 (HSV-1) and type 2 (HSV-2), and vaccinia virus (VV), with good selective index (SI). Among them, the analogue 9c (LAVR-289) proved markedly inhibitory against VZV wild-type (TK+) (EC 50 0.0035 μM, SI 740) and for thymidine kinase VZV deficient strains (EC 50 0.018 μM, SI 145), with a low morphological toxicity in cell culture at 100 μM and acceptable cytostatic activity resulting in excellent selectivity. Compound 9c exhibited antiviral activity against HCMV (EC 50 0.021 μM) and VV (EC 50 0.050 μM), as well as against HSV-1 (TK-) (EC 50 0.0085 μM). Finally, LAVR-289 (9c) deserves further (pre)clinical investigations as a potent candidate broad-spectrum anti-herpesvirus drug. [Display omitted] • Acyclic nucleoside 4-(2,4-diaminopyrimidin-6-yl)oxy-but-2-enyl]phosphonic acid prodrug. • Acyclic cross-metathesis is the key step. • Novel HDP/POC prodrug of acyclic nucleoside phosphonate. • Final compounds exhibited an antiviral activity with μM to nM range on a broad variety of DNA viruses. • LAVR-289 (9c) is potent against VZV virus (EC 50 0.0035 μM) with low toxicity and high selectivity. [ABSTRACT FROM AUTHOR]

Quinoxalines, a class of N-heterocyclic compounds, are important biological agents, and a significant amount of research activity has been directed towards this class. They have several prominent pharmacological effects like antifungal, antibacterial, antiviral, and antimicrobial. Quinoxaline derivatives have diverse therapeutic uses and have become the crucial component in drugs used to treat cancerous cells, AIDS, plant viruses, schizophrenia, certifying them a great future in medicinal chemistry. Due to the current pandemic situation caused by SARS-COVID 19, it has become essential to synthesize drugs to combat deadly pathogens (bacteria, fungi, viruses) for now and near future. Since quinoxalines is an essential moiety to treat infectious diseases, numerous synthetic routes have been developed by researchers, with a prime focus on green chemistry and cost-effective methods. This review paper highlights the various synthetic routes to prepare quinoxaline and its derivatives, covering the literature for the last two decades. A total of 31 schemes have been explained using the green chemistry approach, cost-effective methods, and quinoxaline derivatives' therapeutic uses. [ABSTRACT FROM AUTHOR]

In the last three decades, oligonucleotides have been extensively investigated as probes, molecular ligands and even catalysts within therapeutic and diagnostic applications. The narrow chemical repertoire of natural nucleic acids, however, imposes restrictions on the functional scope of oligonucleotides. Initial efforts to overcome this deficiency in chemical diversity included conservative modifications to the sugar-phosphate backbone or the pendant base groups and resulted in enhanced in vivo performance. More importantly, later work involving other modifications led to the realization of new functional characteristics beyond initial intended therapeutic and diagnostic prospects. These results have inspired the exploration of increasingly exotic chemistries highly divergent from the canonical nucleic acid chemical structure that possess unnatural physiochemical properties. In this review, the authors highlight recent developments in modified oligonucleotides and the thrust towards designing novel nucleic acid-based ligands and catalysts with specifically engineered functions inaccessible to natural oligonucleotides. [ABSTRACT FROM AUTHOR]

Herein, we propose the synthesis of a microspherical imprinted hydrogel meant for the controlled release of a nucleotide, adenosine 5′-monophosphate (5′-AMP). Indeed, molecularly imprinted polymers-based (MIPs) materials possess remarkable selective molecular recognition ability that mimicks biological systems. MIPs have been used in numerous applications and hold great promise for the vectorization and/or controlled release of therapeutics and cosmetics. But, the conception of imprinted hydrogels-based drug delivery systems that are able to release polar bioactive compounds is explored weakly. Herein, the synthesis of imprinted hydrogel microbeads by inverse Pickering emulsion is detailed. Microspheres showed a large 5′-AMP loading capacity, around 300 mg·g−1, and a high binding capacity comparatively to the non-imprinted counterpart. The MIP had a thermo-responsive release behavior providing sustained release of adenosine 5′-monophosphate in an aqueous buffer simulating both human skin pH and temperature. • Molecularly imprinted hydrogel microspheres are prepared by inverse Pickering emulsion. • At the saturation concentration of 15 mg·mL−1 of 5′-AMP in solution, Imprinting Factor was equal to 3. • The imprinted microbeads showed high 5′-AMP loading, around 300 mg·g−1. • The release profile of 5′-AMP from imprinted beads was slower than the non-imprinted one, whatever the temperature. • The hydrogel microspheres were thermosensitive and showed a sustained release at 35 °C comparatively to 25 °C. [ABSTRACT FROM AUTHOR]

Abstract Nucleosides and their analogues play a crucial role in the treatment of several diseases including cancers and viral infections. Their therapeutic efficiency depends on their capacity to be converted to the active nucleoside triphosphates form through successive phosphorylation steps catalyzed by nucleoside/nucleotide kinases. It is thus mandatory to develop an easy, rapid, reliable and sensitive enzyme activity tests. In this study, we monitored the three-step phosphorylation of thymidine to thymidine triphosphate respectively by (1) human thymidine kinase 1 (hTK1), (2) human thymidylate kinase (hTMPK) and (3) human nucleoside diphosphate kinase (hNDPK). Free and immobilized kinase activities were characterized by using the Michaelis-Menten kinetic model. Flow Injection Analysis (FIA) with High-Resolution Mass Spectrometry (HRMS) was used as well as capillary electrophoresis (CE) with UV detection. The three-step cascade phosphorylation of thymidine was also monitored. FIA-HRMS allows a sensitive and rapid evaluation of the phosphorylation process. This study proposes simple, rapid, efficient and sensitive methods for enzyme kinetic studies and successive phosphorylation monitoring with immobilized enzymes. Graphical abstract Image 1 Highlights • Rapid and direct Kinase activity characterization using FIA-HRMS technique. • Free and immobilized kinase activities characterized by Michaelis-Menten. • Monitoring of nucleoside multi-step phosphorylation by FIA-HRMS. • Enzyme immobilization suitable for multi-step enzymatic phosphorylation study. [ABSTRACT FROM AUTHOR]

We report herein the synthesis and biological evaluation of a new series of 2,4,6-trisubstituted 1,3,5-triazines as reversible inhibitors of human cysteine cathepsins. The desired products bearing morpholine and N -Boc piperidine, respectively, were obtained in three to four steps from commercially available trichlorotriazine. Seventeen hitherto unknown compounds were evaluated in vitro against various cathepsins for their inhibitory properties. Among them, compound 7c (4-(morpholin-4-yl)-6-[4-(trifluoromethoxy)anilino]-1,3,5-triazine-2-carbonitrile) was identified as the most potent and selective inhibitor of cathepsin S (Ki  =  2  ±  0.3 nM). Also 7c impaired the autocatalytic maturation of procathepsin S. Molecular docking studies support that 7c bound within the active site of cathepsin S, by interacting with Gly23, Cys25 and Trp26 (S1 subsite), with Asn67, Gly69 and Phe70 (S2 subsite) and with Gln19 (S1′ pocket). [ABSTRACT FROM AUTHOR]

Several hitherto unknown (E) -but-2-enyl nucleoside phosphonoamidate analogs (ANPs) were prepared directed with nitrogen reagents by cross-metathesis in water-under ultrasound irradiation. Two diastereoisomers were formally identified by X-ray diffraction. These compounds were evaluated against a large spectrum of DNA and RNA viruses. Among them, the phosphonoamidate thymine analogue 19 emerged as the best prodrug against varicella-zoster virus (VZV) with EC 50 values of 0.33 and 0.39 μM for wild-type and thymidine kinase deficient strains, respectively, and a selectivity index ≥200 μM. This breakthrough approach paves the way for new purine and pyrimidine (E) -but-2-enyl phosphonoamidate analogs. [ABSTRACT FROM AUTHOR]

The article presents research briefs related to medicinal chemistry, as of January 2018. Topics include a study on an allosteric inhibitor with the most complex mode of action to combat tuberculosis; use of selective indazole ether-based glucocorticoid receptor modulators for treating asthma and chronic obstructive pulmonary disease; and developing potent proteolysis-targeting chimeras (protacs) in anticancer drug discovery.

The synthesis and evaluation against various cysteine cathepsins with endopeptidase activity, of two new families of hitherto unknown 1,3,5-triazines, substituted by a nitrile function and either a cyclohexylamine moiety ( 5 -like) or a piperazine moiety ( 9 -like) are described. The structure-activity relationship was discussed; from 16 synthesized novel compounds, 9h was the most active and selectively inhibitor of Cat K (IC 50 = 28 nM) and Cat S (IC 50 = 23 nM). Molecular docking of 9h to X-ray crystal structure of cathepsins K and S confirmed a common binding mode with a crucial covalent bond with Cys25. We observed for 9h that p -trifluorophenyl group is located in S2 pocket and possess hydrophobic interactions with Tyr67 and Met68. Triazine and piperazine moieties are located in S′1 pocket and interact with Gly23, Cys63, Gly64 and Gly65. Altogether, these results indicate that the new analogs can make them effective agents against some viruses for which the glycoprotein cleavage is mediated by an array of proteases. [ABSTRACT FROM AUTHOR]

Cancer is a leading cause of death worldwide and actual analytical techniques are restrictive in detecting it. Thus, there is still a challenge, as well as a need, for the development of quantitative non-invasive tools for the diagnosis of cancers and the follow-up care of patients. We introduce first the overall interest of electronic nose or tongue for such application of microsensors arrays with data processing in complex media, either gas (e.g., Volatile Organic Compounds or VOCs as biomarkers in breath) or liquid (e.g., modified nucleosides as urinary biomarkers). Then this is illustrated with a versatile acoustic wave transducer, functionalized with molecularly-imprinted polymers (MIP) synthesized for adenosine-5'-monophosphate (AMP) as a model for nucleosides. The device including the thin film coating is described, then static measurements with scanning electron microscopy (SEM) and electrical characterization after each step of the sensitive MIP process (deposit, removal of AMP template, capture of AMP target) demonstrate the thin film functionality. Dynamic measurements with a microfluidic setup and four targets are presented afterwards. They show a sensitivity of 5 Hz.ppm-1 of the non-optimized microsensor for AMP detection, with a specificity of three times compared to PMPA, and almost nil sensitivity to 3'AMP and CMP, in accordance with previously published results on bulk MIP. [ABSTRACT FROM AUTHOR]

An abstract of the article "A Convenient, Highly Selective and Eco-Friendly N-Boc Protection of Pyrimidines under Microwave Irradiation" by M. Bessieres and colleagues is presented.

The synthesis and antiviral evaluation of a series of dihydropyrimidinone and thiopyrimidine derivatives bearing aryl α,γ-diketobutanoic acid moiety are described using the Biginelli multicomponent reaction as key step. The most active among 20 synthesized novel compounds were 4c, 4d and 5b, which possess nanomolar HIV-1 integrase (IN) stand transfer (ST) inhibition activities. In order to understand their mode of interactions within the IN active site, we docked all the compounds into the previously reported X-ray crystal structure of IN. We observed that compounds 4c , 4d and 5b occupied an area close to the two catalytic Mg 2+ ions surrounded by their chelating triad (E221, D128 and D185), DC16, Y212 and the β -diketo acid moiety of 4c , 4d and 5b chelating Mg 2+ . As those compounds lack anti-HIV activities in cell, their prodrugs were synthetized. The prodrug 4c ′ exhibited an anti-HIV activity of 0.19 μM in primary human lymphocytes with some cytotoxicity. All together, these results indicate that the new analogs potentially interact within the catalytic site with highly conserved residues important for IN catalytic activity. [ABSTRACT FROM AUTHOR]

Access to fluoroalkylidene-oxetanes and -azetidines was realized from 3-oxetanone, 3-azetidinone, and fluorosulfones through the Julia-Kocienski reaction. This approach allows the preparation of new precursors of fluorinated four-membered rings that contain a nucleic base, an ester or aryl sulfone function, and a pyrrolidine ring. Benzothiazolyl-sulfone-mediated aza-Michael addition reaction of nitrogen nucleophiles enables access to 3,3-disubstituted oxetanes. [ABSTRACT FROM AUTHOR]

We designed a straightforward biotinylated probe using the N-terminal substrate-like region of the inhibitory site of human cystatin C as a scaffold, linked to the thiol-specific reagent diazomethylketone group as a covalent warhead (i.e. Biot-(PEG) 2 -Ahx-LeuValGly-DMK). The irreversible activity-based probe bound readily to cysteine cathepsins B, L, S and K. Moreover affinity labeling is sensitive since active cathepsins were detected in the nM range using an ExtrAvidin ® -peroxidase conjugate for disclosure. Biot-(PEG) 2 -Ahx-LeuValGly-DMK allowed a slightly more pronounced labeling for cathepsin S with a compelling second-order rate constant for association (k ass = 2,320,000 M −1 s −1 ). Labeling of the active site is dose-dependent as observed using 6-cyclohexylamine-4-piperazinyl-1,3,5-triazine-2-carbonitrile, as competitive inhibitor of cathepsins. Finally we showed that Biot-(PEG) 2 -Ahx-LeuValGly-DMK may be a simple and convenient tool to label secreted and intracellular active cathepsins using a myelomonocytic cell line (THP-1 cells) as model. [ABSTRACT FROM AUTHOR]

A series of imprinted polymers targeting nucleoside metabolites, prepared using a template analogue approach, are presented. These were prepared following selection of the optimum functional monomer by solution association studies using 1 H NMR titrations whereby methacrylic acid was shown to be the strongest receptor with and affinity constant of 621 ± 51 L mol −1 vs. 110 ± 16 L mol −1 for acrylamide. The best performing polymers were prepared using methanol as porogenic co-solvent and although average binding site affinities were marginally reduced, 2.3 × 10 4 L mol −1 vs. 2.7 × 10 4 L mol −1 measured for a polymer prepared in acetonitrile, these polymers contained the highest number of binding sites, 5.27 μmol g −1 vs. 1.64 μmol g −1 , while they also exhibited enhanced selectivity for methylated guanosine derivatives. When applied as sorbents in the extraction of nucleoside derivative cancer biomarkers from synthetic urine samples, significant sample clean-up and recoveries of up to 90% for 7-methylguanosine were achieved. [ABSTRACT FROM AUTHOR]

In this paper, we describe the synthesis and evaluation of molecularly imprinted polymers (MIPs), prepared using 2′,3′,5′-tri- O-acyluridines as 'dummy' templates, for the selective recognition of uridine nucleosides. The MIPs were synthesised using a non-covalent approach with 2,6-bis-acrylamidopyridine (BAAPy) acting as the binding monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent. The MIPs were evaluated in terms of capacity, selectivity and specificity by analytical and frontal liquid chromatography measurements. The results obtained in organic mobile phases suggest that the nucleosides are specifically bound to the polymer by the complementary hydrogen bonding motifs of the binding monomer and the nucleoside bases. The MIPs exhibited relatively high imprinting factors for 2′,3′,5′-tri- O-acyluridines, while they did not show any binding capacity for other nucleosides lacking the imide moiety on their base. Moreover, the presence of ester-COO groups in the EGDMA cross-linker may lead to the formation of additional hydrogen bonds with the 2′,3′ and/or 5′-OH of sugar part, allowing enhancement of the recognition of the uridine nucleosides. In aqueous media, results show that the binding is driven by hydrophobic interactions. [ABSTRACT FROM AUTHOR]

Intermolecular ultrasound-assisted olefin cross-metathesis is reported. This approach allows an easy access to challenging trisubstituted alkenyl nucleoside phosphonates. Regioselective chemoenzymatic deacetylation and Mitsunobu coupling are also described. [ABSTRACT FROM AUTHOR]

Abstract: A series of seventeen hitherto unknown ANP analogs bearing the (E)-but-2-enyl aliphatic side chain and modified heterocyclic base such as cytosine and 5-fluorocytosine, 2-pyrazinecarboxamide, 1,2,4-triazole-3-carboxamide or 4-substituted-1,2,3-triazoles were prepared in a straight approach through an olefin acyclic cross metathesis as key synthetic step. All novel compounds were evaluated for their antiviral activities against a large number of DNA and RNA viruses including herpes simplex virus type 1 and 2, varicella zoster virus, feline herpes virus, human cytomegalovirus, hepatitis C virus (HCV), HIV-1 and HIV-2. Among these molecules, only compound 31 showed activity against human cytomegalovirus in HEL cell cultures with at EC50 of ∼10 μM. Compounds 8a, 13, 14, and 24 demonstrated pronounced anti-HCV activity without significant cytotoxicity at 100 μM. [Copyright &y& Elsevier]

Highlights: [•] Monomer for MIP of vanillin were chosen on molecular modelling calculations. [•] MIP was synthesized by both non-covalent and semi-covalent approach. [•] Binding characteristics and specificity of MIP were evaluated. [•] MISPE method was developed for analysis of vanillin in wine. [Copyright &y& Elsevier]

Under optimized conditions, the Sonogashira coupling of substrate (I) with alkynes is followed by cyclization. [ABSTRACT FROM AUTHOR]

Abstract: Seventeen hitherto unknown bis(POM) prodrugs of novel (E)-[4′-phosphono-but-2′-en-1′-yl]purine nucleosides were prepared in a straight approach and at good yields. Those compounds were synthesized by the reaction of purine nucleobases directly with the phosphonate synthon 3 bearing POM biolabile groups under Mitsunobu conditions. All obtained compounds were evaluated for their antiviral activities against a large number of DNA and RNA viruses including herpes simplex viruses 1 and 2, varicella zoster virus, Feline herpes virus, human cytomegalovirus, HIV-1 and HIV-2. Among these molecules, some of them exhibit anti-VZV and anti-HIV activity at submicromolar concentrations. This class of compound will be of further interest for lead optimization as anti-infectious agents. [Copyright &y& Elsevier]

Abstract: Fructosazine and 2,5-deoxyfructosazine are two natural chemicals with various applications as flavoring agents in food and tobacco industry; the 2,5-deoxyfructosazine has also anti-diabetic and anti-inflammatory activities. In order to quantify these compounds in natural samples such as plant or food, we have developed a selective technique based on a water-compatible molecularly imprinted polymer (MIP). MIPs are prepared with a covalent approach from 2,5-deoxyfructosazine as template formed in situ by the self-condensation of glucosamine with vinylphenyl boronic acid, taken as catalyst and covalent monomer during the pre-complexation step. Acrylamide and polyethylene glycol diacrylate are used as supplementary non-covalent functional monomer and cross-linker, respectively. For the first time, a highly cross-linked but highly polar imprinted polymer of fructosazine and deoxyfructosazine is obtained as a solid material and not a gel. Amount of monomers is optimized to obtain high selectivity for both molecules. Results show that the MIPs prepared have a significant imprinting effect with a resulting imprinting factor of 3 for both templates. Molecularly imprinted solid-phase extraction is then performed and could be used in routine analysis to extract 2,5-deoxyfructosazine and fructosazine from soy sauce. [Copyright &y& Elsevier]

Abstract: Starting from acetylated 5-ethynyl-2′-deoxyuridine (3), 14 hitherto unknown C5-substituted-(1,3-diyne)-2′-deoxyuridines (with cyclopropyl, hydroxymethyl, methylcyclopentane, p-(substituted)phenyl and disubstituted-phenyl substituents) have been synthesized via a nickel-copper catalyzed C–H activation between two terminal alkynes, in yields ranging from 19% to 67%. Their antiviral activities were measured against a large number of DNA and RNA viruses including herpes simplex virus type 1 and type 2, varicella-zoster virus, human cytomegalovirus and vaccinia virus. The 5-[4-(4-trifluoromethoxyphenyl)buta-1,3-diynyl]-2′-deoxyuridine (26) is the most potent inhibitor of this series against VZV with an EC50 of ∼1 μM and a CC50 of 55 μM. Their cytostatic activities were determined against murine leukemia cells, human T-lymphocyte cells and cervix carcinoma cells. Compounds were also evaluated on a wide panel of RNA viruses, including influenza virus A (H1N1 and H3N2) and B in MDCK cell cultures, parainfluenza-3 virus, reovirus-1, Sindbis virus and Punta Toro virus in Vero cell cultures and vesicular stomatitis, coxsackie B4 and respiratory syncytial virus in HeLa cell cultures and against human immunodeficiency virus type 1 and 2 in CEM cell cultures, with no specific antiviral effect. This class of compounds could be of further interest for lead optimization as anti-infectious (i.e. herpetic) agents. [Copyright &y& Elsevier]

Abstract: A series of unsaturated acyclonucleoside bis(POC) prodrugs of E configuration were synthesized through an expeditious, highly efficient and stereoselective one-step procedure from corresponding bis(POC)allylphosphonate through Ru catalyzed cross-coupling metathesis reaction. The [RuCl2(PCy3)(SIPr)(Indenylidene)] and [RuCl2(PCy3)(IMes)(benzylidene)] catalysts were employed; the unsaturated ANP were used bore C5-halovinyl uracil, C5-dihalovinyluracil or furanopyrimidine motifs. The chemical cleavage of biolabile (POC) group is a useful pathway to acid phosphonate derivatives. [Copyright &y& Elsevier]

Abstract: The synthesis and antiviral evaluation of a series of C5-(1,4- and 1,5-disubstituted-1,2,3-triazolo)-nucleoside derivatives is described. The key steps of this synthesis are regioselective Huisgen’s 1,3-dipolar cycloaddition, using either copper-catalyzed azide-alkyne cycloaddition (CuAAC) or ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) under microwave activation. Some compounds among the 5a–l series possess activity against herpes simplex viruses 1 and 2, varicella-zoster virus, human cytomegalovirus and vaccinia virus. Their cytostatic activities were determined against murine leukemia cells, human T-lymphocyte cells and cervix carcinoma cells. Compounds were also evaluated on a wide panel of RNA viruses, including Vesicular stomatitis virus, influenza viruses type A (H1N1 and H3N2) and B in MDCK cell cultures, parainfluenza-3 virus, reovirus-1, Sindbis virus and Punta Toro virus in Vero cell cultures and Vesicular stomatitis, Coxsackie B4 and respiratory syncytial virus, with no specific antiviral effect. [ABSTRACT FROM AUTHOR]

Abstract: The pathogenic mycoplasma Ureaplasma parvum (Up) causes opportunistic infections and relies on salvage of nucleosides for DNA synthesis and Up thymidine kinase (UpTK) provides the necessary thymidine nucleotides. The anti-HIV compound 3´-azido-3′-deoxythymidine (AZT) is a good substrate for TK. Methods for a rapid and efficient synthesis of new 3′-α-[1,2,3]triazol-3′-deoxythymidine analogs from AZT under Huisgen conditions are described. Thirteen 3′-analogues were tested with human cytosolic thymidine kinase (hTK1) and UpTK. The new analogs showed higher efficiencies (K m/V max values) in all cases with UpTK than with hTK1. Still, hTK1 was preferentially inhibited by 9 out of 10 tested analogs. Structural models of UpTK and hTK1 were constructed and used to explain the kinetic results. Two different binding modes of the nucleosides within the active sites of both enzymes were suggested with one predominating in the bacterial enzyme and the other in hTK1. These results will aid future development of anti-mycoplasma nucleosides. [Copyright &y& Elsevier]

Abstract: Antiviral nucleoside and nucleotide analogs, essential for the treatment of viral infections in the absence of efficient vaccines, are prodrug forms of the active compounds that target the viral DNA polymerase or reverse transcriptase. The activation process requires several successive phosphorylation steps catalyzed by different kinases, which are present in the host cell or encoded by some of the viruses. These activation reactions often are rate-limiting steps and are thus open to improvement. We review here the structural and enzymatic properties of the enzymes that carry out the activation of analogs used in therapy against human immunodeficiency virus and against DNA viruses such as hepatitis B, herpes and poxviruses. Four major classes of drugs are considered: thymidine analogs, non-natural l-nucleosides, acyclic nucleoside analogs and acyclic nucleoside phosphonate analogs. Their efficiency as drugs depends both on the low specificity of the viral polymerase that allows their incorporation into DNA, but also on the ability of human/viral kinases to provide the activated triphosphate active forms at a high concentration at the right place. Two distinct modes of action are considered, depending on the origin of the kinase (human or viral). If the human kinases are house-keeping enzymes that belong to the metabolic salvage pathway, herpes and poxviruses encode for related enzymes. The structures, substrate specificities and catalytic properties of each of these kinases are discussed in relation to drug activation. [Copyright &y& Elsevier]

Abstract: The palladium-catalyzed reaction of 5-tributylstannyluridine derivative (9) with a variety of aryl, vinyl halides provides an efficient method for the synthesis of the corresponding 5-substituted 6,5′-O-anhydrouridines. Additionally the 5-fluoro 6,5′-O-anhydrouridine (16) via fluoro-destannylation with Selectfluor is described. A dialkylphosphonate moiety was then introduced at C5 from the allyl derivative 10a under cross-metathesis conditions. [Copyright &y& Elsevier]

Abstract: Vaccinia virus thymidylate kinase, although similar in sequence to human TMP kinase, has broader substrate specificity and phosphorylates (E)-5-(2-bromovinyl)-dUMP and dGMP. Modified guanines such as glyoxal-dG, 8-oxo-dG, O6-methyl-dG, N2-ethyl-dG and N7-methyl-dG were found present in cancer cell DNA. Alkylated and oxidized dGMP analogs were examined as potential substrates for vaccinia TMP kinase and also for human TMP and GMP kinases. Molecular models obtained from structure-based docking rationalized the enzymatic data. All tested nucleotides are found surprisingly substrates of vaccinia TMP kinase and also of human GMP kinase. Interestingly, O6-methyl-dGMP is the only analog specific for the vaccinia enzyme. Thus, O6-Me-dGMP could be useful for designing new compounds of medical interest either in antipoxvirus therapy or in experimental combined gene/chemotherapy of cancer. These results also provide new insights regarding dGMP analog reaction with human GMP kinase and their slow recycling by salvage pathway nucleotide kinases. [Copyright &y& Elsevier]

Abstract: The synthesis of hitherto unknown C5-substituted O 6,5′-cyclouridines is described. The 2′,3′-isopropylidene-uridine was treated with N-halogenosuccinimides forming appropriate bridged 5-halogeno derivatives. Using lithiation method, bromine substituent at C5 position was exchanged into various alkyl and alkenyl derivatives. [Copyright &y& Elsevier]