Acid-Base Equilibrium of 5,5,6-Trihydroxy-6-Methyldihydropyrimidine-2,4(1,3)-Dione in the Gas Phase and in Water.

The first-stage acid-base equilibrium of 5,5,6-trihydroxy-6-methyldihydropyrimidine-2,4(1,3)-dione was studied for the first time in aqueous solutions. Its constant (pK = 9.23 ± 0.

Conjugation of Triterpenic Acids with 3-Aminoquinuclidine Moiety: An Approach to Acetylcholinesterase Mixed or Uncompetitive Type Inhibitors.

Alzheimer's disease (AD) poses a significant public health issue. Despite the fact that today there are several methods of maintenance therapy, one of the most widely used methods is designed to correct the deficiency of acetylcholine. In the search for new potential inhibitors of cholinesterase enzymes, eight new derivatives of 3-oxo- or 2,3-indolo-triterpenic acid conjugated with amino-quinuclidine bicyclic cores were designed and synthesized.

Discovery of Potent Dengue Virus NS2B-NS3 Protease Inhibitors Among Glycyrrhizic Acid Conjugates with Amino Acids and Dipeptides Esters.

This study investigated a library of known and novel glycyrrhizic acid (GL) conjugates with amino acids and dipeptide esters, as inhibitors of the DENV NS2B-NS3 protease. We utilized docking algorithms to evaluate the interactions of these GL derivatives with key residues (His51, Asp75, Ser135, and Gly153) within 10 Å of the DENV-2 NS2B-NS3 protease binding pocket (PDB ID: 2FOM). It was found that compounds and exhibited unique binding patterns, forming hydrogen bonds with Asp75, Tyr150, and Gly153.

Effect of Herbicide-Resistant Oil-Degrading Bacteria on Plants in Soil Contaminated with Oil and Herbicides.

Biological remediation of agricultural soils contaminated with oil is complicated by the presence of residual amounts of chemical plant protection products, in particular, herbicides, which, like oil, negatively affect the soil microbiome and plants. In this work, we studied five strains of bacteria of the genera and , which exhibited a high degree of oil biodegradation (72-96%). All strains showed resistance to herbicides based on 2,4-D, imazethapyr and tribenuron-methyl, the ability to fix nitrogen, phosphate mobilization, and production of indole-3-acetic acid.

Thermal Degradation Study of Hydrogel Nanocomposites Based on Polyacrylamide and Nanosilica Used for Conformance Control and Water Shutoff.

The application of nanocomposites based on polyacrylamide hydrogels as well as silica nanoparticles in various tasks related to the petroleum industry has been rapidly developing in the last 10-15 years. Analysis of the literature has shown that the introduction of nanoparticles into hydrogels significantly increases their structural and mechanical characteristics and improves their thermal stability. Nanocomposites based on hydrogels are used in different technological processes of oil production: for conformance control, water shutoff in production wells, and well killing with loss circulation control.

Solvate Complex LiAlCl·SO: Synthesis and Physical-Chemical Properties.

This work describes the synthesis of the LiAlCl·SO solvate complex and its properties. Its composition was determined using thermogravimetric analysis, Raman spectroscopy, and UV-vis spectroscopy. The specific ionic conductivity of LiAlCl·SO is 4.

2-Arylhydrazinylidene-3-oxo-3-polyfluoroalkylpropanoic acids as selective and effective carboxylesterase inhibitors with powerful antioxidant potential.

A series of 2-arylhydrazinylidene-3-oxo acids (AHOAs) was prepared by dealkylation of alkyl-2-arylhydrazinylidene-3-oxo-3-alkanoates with AlBr. Using X-Ray, NMR spectroscopy, and quantum mechanical calculations (QM), the existence of AHOAs in a thermodynamically favorable Z-form stabilized by two intramolecular H-bonds was established. All AHOAs had acceptable ADME parameters.

Efficient modification of peroxydisulfate oxidation reactions of nitrogen-containing heterocycles 6-methyluracil and pyridine.

Nitrogen-containing heterocyclic compounds are widely used in pharmacology due to their pronounced biological activities and low toxicities. The introduction of a hydroxy function into uracil and pyridine molecules has led to compounds with antioxidant, anti-inflammatory, and immunomodulatory activity (3-hydroxy-6-methyl-2-ethylpyridine, 5-hydroxy-6-methyluracil, etc.).

Phage Display Revealed the Complex Structure of the Epitope of the Monoclonal Antibody 10H10.

The annual number of reported human cases of flavivirus infections continues to increase. Measures taken by local healthcare systems and international organizations are not fully successful. In this regard, new approaches to treatment and prevention of flavivirus infections are relevant.

New Cytotoxic α-Aminoacylamide and bis-1,5-Disubstituted Tetrazole Adducts From Amino-Diterpene Molecules by Ugi Reaction.

In search for new molecules of diterpene origin with promising anticancer activity, two amino-derivatives (methyl maleopimarate aminoimide and methyl 1β,13-epoxydihydroquinopimarate C4-hydrazone) were involved in the 4-component Ugi reaction (Ugi-4CR) and pseudo-7-component azido-Ugi condensation (azido-Ugi-7CR) to afford a series of adducts holding α-aminoacylamide and bis-1,5-disubstituted tetrazole substituents. The NCI-60 cancer cell panel screening revealed diterpene-type Ugi adducts 2, 5, and 6 with strong antiproliferative potency with GI in range of 1.2-15.

A Novel Dipterocarpol Derivative That Targets Alpha-Glucosidase and NLRP3 Inflammasome Activity for Treatment of Diabetes Mellitus.

Type 2 diabetes mellitus is a chronic metabolic disorder characterized by persistent hyperglycemia, chronic inflammation, impaired insulin secretion, and/or peripheral insulin resistance. Current α-glucosidase inhibitors approved for clinical use exhibit limited efficacy compared to other glucose-lowering agents. In this study, a series of mono- and bis-benzylidene derivatives were synthesized via aldol condensation of 3-oxo-dammarane triterpenoids with terephthalic aldehyde.

Assessing the inhibitory effects of some secondary amines, thioureas and 1,3-dimethyluracil conjugates of (-)-cytisine and thermopsine on the RNA-dependent RNA polymerase of SARS-CoV-1 and SARS-CoV-2.

SARS-CoV-2 causes COVID-19, with symptoms ranging from mild to severe, including pneumonia and death. This beta coronavirus has a 30-kilobase RNA genome and shares about 80 % of its nucleotide sequence with SARS-CoV-1. The replication/transcription complex, essential for viral RNA synthesis, includes RNA-dependent RNA polymerase (RdRp, nsp12) enhanced by nsp7 and nsp8.

Ursolic acid-based 24-nor- and A--24-oxy-triterpenoids.

Using methyl 2-cyano-3,4--12(13),4(23)-diene-ursolate as a starting scaffold a series of 3-oxo-24-nor-ursolate and A--ursanes holding hydroxy-, furoyloxy-, -tosyloxy- as well as aldehyde fragments at C24 that possess cytotoxic activity has been synthesised. The structures of the new ursanes were confirmed by detailed spectral data analysis. The chemoselectivity of methyl 2-cyano-3,4--12(13),4(23)-diene-ursolate oxidation involving the double bond in the A cycle was observed.

One-Stage Pathway from Hollongdione to C17-Alkyne and Vinyl Chloride Following Mannich Bases and Carboxylic Acid.

Hollongdione is the first recorded example of the occurrence of a dammarane hexanor-triterpene in nature possessing antiviral and cytotoxic activity. Its simple one-stage transformation into compounds with terminal alkyne and vinyl chloride fragments via the interaction with phosphorus halides is reported. The copper(I)-catalyzed Mannich reaction of 3-oxo-22,23,24,25,26,27-hexanor-dammar-20(21)-in led to a series of aminomethylated products, while 17-carboxylic acid was obtained by ozone oxidation of 3-oxo-22,23,24,25,26,27-hexanor-dammar-20-chloro-20(21)-en ; the following direct amidation of the latter has been developed.

Derivatization of Abietane Acids by Peptide-like Substituents Leads to Submicromolar Cytotoxicity at NCI-60 Panel.

Natural compounds, including diterpenoids, play a critical role in various biological processes and are recognized as valuable components in cancer treatment. Isocyanides multicomponent reactions (IsMCRs) are one of the effective methods to obtain adducts at the carboxyl group with a peptide-like substituent. In this study, dehydroabietic acid and levopimaric acid diene adducts as the starting scaffolds were modified by the multicomponent Passerini (P-3CR) and Ugi (U-4CR) reactions to afford α-acyloxycarboxamides and α-acylaminocarboxamides.

Structure and Physicochemical Properties of Solutions of Lithium Polysulfides in Tetrasolvate of Lithium Perchlorate with Sulfolane Molecular Dynamics Modeling.

Lithium polysulfides are intermediate products formed during the discharge and charge of lithium-sulfur batteries and have good solubility in electrolyte solutions. Therefore, the properties and structure of solutions of lithium polysulfides in electrolyte solutions affect the energy characteristics of the lithium-sulfur battery. In this work, the structure and physicochemical properties (density, ionic conductivity, and self-diffusion coefficients) of solutions of lithium disulfide, tetrasulfide, and octasulfide in lithium perchlorate tetrasolvate with sulfolane in a wide range of concentrations (0.

Glycyrrhizic acid conjugates with amino acid methyl esters target the main protease, exhibiting antiviral activity against wild-type and nirmatrelvir-resistant SARS-CoV-2 variants.

COVID-19 pandemic is predominantly caused by SARS-CoV-2, with its main protease, Mpro, playing a pivotal role in viral replication and serving as a potential target for inhibiting different variants. In this study, potent Mpro inhibitors were identified from glycyrrhizic acid (GL) derivatives with amino acid methyl/ethyl esters. Out of the 17 derivatives semisynthesized, Compounds 2, 6, 9, and 15, with methionine methyl esters, D-tyrosine methyl esters, glutamic acid methyl esters, and methionines in the carbohydrate moiety, respectively, significantly inhibited wild-type SARS-CoV-2 Mpro-mediated proteolysis, with IC50 values ranging from 0.

Novel binuclear copper(II) complexes with sulfanylpyrazole ligands: synthesis, crystal structure, fungicidal, cytostatic, and cytotoxic activity.

New binuclear copper(II) [Cu(II)] tetraligand complexes (six examples) with sulfanylpyrazole ligands were synthesized. Electron spin resonance (ESR) studies have shown that in solution the complexes are transformed to the mononuclear one. Fungicidal properties against Candida albicans were found for the Cu complexes with benzyl and phenyl substituents.

Synthesis and bioevaluation of water-soluble -cyclodextrin-diterpene acid conjugates.

A series of -cyclodextrin (-CD)-conjugates were prepared by combining three abietane-type diterpene acids with two azide-functionalized -CDs via click chemistry, and the antiviral activity against wild-type and omicron SARS-CoV-2 spike pseudovirus as well as the antibacterial activity against were investigated. All the synthesised conjugates exhibited no significant cytotoxicity to BHK-21-hACE2 cells with cell viability over 80% at concentration of 15 M. Among the conjugates, the heptavalent -CD-dehydroabietic acid conjugate exhibited higher anti-SARS-CoV-2 activity against the omicron variant compared to the other conjugates.

Use of Self-Generating Foam Gel Composition with Subsequent Injection of Hydrogel to Limit Gas Inflow in Horizontal Wells of Vostochno-Messoyakhskoye Field.

Gas inflow control in oil wells is one of the most challenging types of repair and sealing operations, the success rate of which does not exceed, as a rule, 30%. Conventional shutoff methods are often ineffective for this purpose. For instance, cement solutions cannot be injected into wells in the required volumes, while gel screens can only temporarily block the breakthrough zones, as gas easily seeps through the gel, forming new channels for gas inflow.

Removal of Anionic Methyl Orange Dye from Water by Poly[2-methyl-1-indole] Derivatives: Investigation of Kinetics and Isotherms of Adsorption.

The adsorption properties toward methyl orange (MO) were evaluated for poly[2-methyl-1-indole] and its derivatives. The influence of pH, ionic strength of solution, composition, and amount of sorbent on the adsorption of MO dye was investigated; the kinetics of dye adsorption was studied. The adsorption isotherms were analyzed using different models of sorption equilibrium.

Diethoxyphosphoryloxy-oleanolic acid is a nanomolar-inhibitor of butyrylcholinesterase.

A series of new betulin, lupeol, erythrodiol, and oleanolic acid phosphoryloxy- and furoyloxy-derivatives has been synthesized and their structure was confirmed by NMR spectroscopy. Synthesized compounds were subjected to Ellman's assays to determine their ability to inhibit the enzymes AChE and BChE. Among them, diethoxyphosphoryloxy-oleanolic acid inhibited BChE with a value of 99%, thereby acting as a mixed-type inhibitor holding very low K values of Ki = 6.

Synthesis, modification and biological activity of 2,3-indoles of Glycyrrhetinic acid.

The synthesis of 2,3-indoles of Glycyrrhetinic acid (GLA) and its methyl ester was carried out by the Fischer reaction. Reductive transformations of GLA methyl ester 2,3-indole were carried out to obtain 11-deoxo- and 9,12-diene analogs. N-methylation of 2,3-indole gave N-methyl-indole-11-oxo-18β-olean-12-en-30-oic acid.

The Nitro Group Reshapes the Effects of Pyrido[3,4-]quinazoline Derivatives on DYRK/CLK Activity and RNA Splicing in Glioblastoma Cells.

Serine-threonine protein kinases of the DYRK and CLK families regulate a variety of vital cellular functions. In particular, these enzymes phosphorylate proteins involved in pre-mRNA splicing. Targeting splicing with pharmacological DYRK/CLK inhibitors emerged as a promising anticancer strategy.