Dual-Reporter SARS-CoV-2 Replicon for Screening Viral Polymerase Inhibitors.

To design a safe cellular system for testing inhibitors targeting the RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2, a genetic construct was engineered containing viral cDNA with two blocks of reporter genes while the genes encoding structural S, E, and M proteins were absent. The first reporter block, consisting of Renilla luciferase and green fluorescent protein (Rluc-GFP), was located upstream of the SARS-CoV-2 5'-UTR. Meanwhile, the second block represented by firefly luciferase and red fluorescent protein (Fluc-RFP) was positioned downstream of the transcription regulatory sequence (TRS-N).

New Biocides Based on -Alkylcytidines: Effects on Microorganisms and Application for the Protection of Cultural Heritage Objects of Painting.

The rapid increase in the antibiotic resistance of microorganisms, capable of causing diseases in humans as destroying cultural heritage sites, is a great challenge for modern science. In this regard, it is necessary to develop fundamentally novel and highly active compounds. In this study, a series of -alkylcytidines, including 5- and 6-methylcytidine derivatives, with extended alkyl substituents, were obtained in order to develop a new generation of antibacterial and antifungal biocides based on nucleoside derivatives.

5-Substituted Uridines with Activity against Gram-Positive Bacteria.

The emergence of drug-resistant strains of pathogenic microorganisms necessitates the creation of new drugs. A series of uridine derivatives containing an extended substituent at the C-5 position as well as C-5 alkyloxymethyl, alkylthiomethyl, alkyltriazolylmethyl, alkylsulfinylmethyl and alkylsulfonylmethyl uridines were obtained in order to explore their antimicrobial properties and solubility. It has been shown that new ribonucleoside derivatives have an order of magnitude better solubility in water compared to their 2'-deoxy analogues and effectively inhibit the growth of a number of Gram-positive bacteria, including resistant strains of Mycobacterium smegmatis (MIC=15-200 μg/mL) and Staphylococcus aureus (MIC=25-100 μg/mL).

Discovery of novel N-alkylcytidines as promising antimicrobial agents.

The emergence of drug-resistant strains of pathogenic microorganisms necessitates the creation of new drugs. In order to find new compounds that effectively inhibit the growth of pathogenic bacteria and fungi, we synthesized a set of N-derivatives of cytidine, 2'-deoxycytidine and 5-metyl-2'-deoxycytidine bearing extended N-alkyl and N-phenylalkyl groups. The derivatives demonstrate activity against a number of Gram-positive bacteria, including Mycobacterium smegmatis (MIC = 24-200 μM) and Staphylococcus aureus (MIC = 50-200 μM), comparable with the activities of some antibiotics in medical use.

Synthesis of water-soluble prodrugs of 5-modified 2'-deoxyuridines and their antibacterial activity.

Recently we have synthesized a set of pyrimidine nucleoside derivatives bearing extended alkyltriazolylmethyl substituents at position 5 of the nucleic base, and showed their significant activity against Mycobacterium tuberculosis virulent laboratory strain H37Rv as well as drug-resistant MS-115 strain. The presence of a lengthy hydrophobic substituent leads to the reduction of nucleoside water solubility making their antibacterial activity troublesome to study. A series of water-soluble forms of 5-modified 2'-deoxyuridines 4a-c and 8a-c were synthesized.

Versatile synthesis of oxime-containing acyclic nucleoside phosphonates--synthetic solutions and antiviral activity.

New oxime-containing acyclic nucleoside phosphonates 9-{2-[(phosphonomethyl)oximino]ethyl}adenine (1), -guanine (2) and 9-{2-[(phosphonomethyl)oximino]propyl}adenine (3) with wide spectrum activity against different types of viruses were synthesized. The key intermediate, diethyl aminooxymethylphosphonate, was obtained by the Mitsunobu reaction. Modified conditions for the by-product separation (without chromatography and distillation) allowed us to obtain 85% yield of the aminooxy intermediate.

Crystal structure of ammonium 3'-azido-3'-de-oxy-thymidine-5'-amino-carbonyl-phospho-nate hemi-hydrate: an anti-HIV agent.

The asymmetric unit of the title compound, NH4 (+)·C11H14N6O7P(-)·0.5H2O, contains one 3'-azido-3'-de-oxy-thymidine-5'amino-carbonyl-phospho-nate (ACP-AZT) anion, half of an NH4 (+) cation lying on a twofold rotation axis and in another position, occupied with equal probabilities of 0.5, an NH4 (+) cation and a water mol-ecule.

New dinucleoside phosphonate derivatives as prodrugs of 3'-azido-3'-deoxythymidine and β-L-2',3'-dideoxy-3'-thiacytidine: synthesis and anti-HIV properties.

[Formula: see text]New phosphonate homodimers of 3'-azido-3'-deoxythymidine (AZT) and a phosphonate heterodimer of β-L-2',3'-dideoxy-3'-thiacytidine (3TC) and AZT were synthesized. The compounds demonstrated moderate anti-HIV activity. Stability of the compounds in human blood serum was studied.

Synthesis and anti-HIV properties of new carbamate prodrugs of AZT.

A series of new 5'-O-carbamate prodrugs of AZT have been prepared. The stability in biological media, anti-HIV properties and pharmacokinetic parameters in dogs were evaluated. The compounds display moderate anti-HIV activity in cell culture.

Phosphoramidate derivatives of acyclovir: synthesis and antiviral activity in HIV-1 and HSV-1 models in vitro.

The antiviral activity against HIV and HSV and the chemical stability of ACV phosphoramidate derivatives were studied. The phosphoramidates of ACV demonstrated moderate activity. The best compound appeared to be 9-(2-hydroxymethyl)guanine phosphoromonomorpholidate (7), which inhibited virus replication in pseudo-HIV-1 particles by 50% at 50 μM.

5'-phosphonate derivatives of 2',3'-dideoxy-3'-thiacytidine as new anti-HIV prodrugs.

Two new phosphonate 3TC prodrugs were synthesized and studied in MT-4 cells as inhibitors of HIV replication. Their pharmacokinetic parameters were evaluated following intragastric administration in rabbits and oral administration in dogs. Both compounds were much less toxic than parent 3TC in cell cultures and could generate the active nucleoside in laboratory animals.

5'-aminocarbonyl phosphonates as new zidovudine depot forms: antiviral properties, intracellular transformations, and pharmacokinetic parameters.

The main disadvantages of 3'-azido-3'-deoxythymidine (zidovudine, AZT), the most common anti-HIV drug, are toxicity and a short half-life in the organism. The introduction of an H-phosphonate group into the AZT 5' position resulted in significant improvement of its therapeutic properties and allowed a new anti-HIV drug, Nikavir (AZT H-phosphonate). In this work, we described a new group of AZT derivatives, namely, AZT 5'-aminocarbonylphosphonates.

Cell metabolism of acyclovir phosphonate derivatives and antiherpesvirus activity of their combinations with alpha2-interferon.

The combinational use of acyclovir (ACV) phosphonate esters and alpha(2)-interferon was shown to produce a synergistic effect on inhibition of HSV-1 replication in Vero cell cultures. Unlike other acyclovir phosphonate derivatives studied earlier, ACV H-phosphonate is not an ACV prodrug. On penetrating into the cells, it may be directly converted into ACV monophosphate escaping dephosphonylation-phosphorylation steps.

New triphosphate conjugates bearing reporter groups: labeling of DNA fragments for microarray analysis.

A simple and convenient method for incorporation of fluorescent or ligand groups into 3'-termini of DNA fragments is proposed. A set of triphosphoric acid monoesters bearing fluorescent groups or biotin attached to the triphosphate fragment through linkers of different lengths and structures was synthesized. All the compounds were substrates for calf thymus terminal deoxynucleotidyltransferase and were used for incorporation of marker groups into 3'-termini of DNA fragments.

Uncharged AZT and D4T derivatives of phosphonoformic and phosphonoacetic acids as anti-HIV pronucleosides.

Two series of new lipophilic phosphonoformate and phosphonoacetate derivatives of AZT and d4T were synthesized and evaluated as anti-HIV agents. The efficacy of some of the synthesized compounds in cell cultures infected with HIV-1 was higher than that of the parent nucleosides and only slightly correlated to their stability in the phosphate buffer and human blood serum. The synthesized phosphonates are most probably prodrug forms of the corresponding nucleosides.

New lipophilic derivatives of AZT and d4T 5'-phosphonates.

5'-Aminocarbonylphosphonyl and aminocarbonylmethylphosphonyl diesters of AZT and d4T were synthesized as potential anti-HIV agents.

Synthesis and antiherpetic activity of acyclovir phosphonates.

Phosphonate derivatives of acyclovir containing phosphorous acid and ethoxycarbonylphosphonic acid residues as well as their isopropyl esters were prepared. They selectively inhibited the herpes simplex virus 1 reproduction in Vero cell culture, the efficacy of esters being 3-4 times higher than that of ACV. The hydrolysis of the synthesized compounds was studied in the PBS buffer and human blood serum.